diff --git a/api/s10_status.py b/api/s10_status.py
index cf07ccb..33b2a7d 100644
--- a/api/s10_status.py
+++ b/api/s10_status.py
@@ -84,9 +84,9 @@ def inp_in_status(line: str) -> str:
     link = str(tokens[0])
     value = tokens[1].upper()
     if value == LINK_STATUS_OPEN or value == LINK_STATUS_CLOSED or value == LINK_STATUS_ACTIVE:
-        return f"insert into status (link, status, setting) values ('{link}', '{value}', null);"
+        return str(f"insert into status (link, status, setting) values ('{link}', '{value}', null);")
     else:
-        return f"insert into status (link, status, setting) values ('{link}', null, {float(value)});"
+        return str(f"insert into status (link, status, setting) values ('{link}', null, {float(value)});")
 
 
 def inp_out_status(name: str) -> list[str]:
diff --git a/api/s12_curves.py b/api/s12_curves.py
index 1ea6456..eb37982 100644
--- a/api/s12_curves.py
+++ b/api/s12_curves.py
@@ -151,7 +151,7 @@ def delete_curve(name: str, cs: ChangeSet) -> ChangeSet:
 
 def inp_in_curve(line: str) -> str:
     tokens = line.split()
-    return f"insert into curves (id, x, y) values ('{tokens[0]}', {float(tokens[1])}, {float(tokens[2])});"
+    return str(f"insert into curves (id, x, y) values ('{tokens[0]}', {float(tokens[1])}, {float(tokens[2])});")
 
 
 def inp_out_curve(name: str) -> list[str]:
diff --git a/api/s13_controls.py b/api/s13_controls.py
index b3cf9b7..7b43f2b 100644
--- a/api/s13_controls.py
+++ b/api/s13_controls.py
@@ -45,7 +45,7 @@ def set_control(name: str, cs: ChangeSet) -> ChangeSet:
 
 
 def inp_in_control(line: str) -> str:
-    return f"insert into controls (line) values ('{line}');"
+    return str(f"insert into controls (line) values ('{line}');")
 
 
 def inp_out_control(name: str) -> list[str]:
diff --git a/api/s14_rules.py b/api/s14_rules.py
index b7f9e9a..b210f71 100644
--- a/api/s14_rules.py
+++ b/api/s14_rules.py
@@ -41,7 +41,7 @@ def set_rule(name: str, cs: ChangeSet) -> ChangeSet:
 
 
 def inp_in_rule(line: str) -> str:
-    return f"insert into rules (line) values ('{line}');"
+    return str(f"insert into rules (line) values ('{line}');")
 
 
 def inp_out_rule(name: str) -> list[str]:
diff --git a/api/s15_energy.py b/api/s15_energy.py
index cc04c6c..3abb998 100644
--- a/api/s15_energy.py
+++ b/api/s15_energy.py
@@ -153,7 +153,7 @@ def inp_in_energy(line: str) -> str:
         if key == 'efficiency':
             key = 'effic'
 
-        return f"insert into energy_pump_{key} (pump, {key}) values ('{pump}', {value});"
+        return str(f"insert into energy_pump_{key} (pump, {key}) values ('{pump}', {value});")
 
     else:
         line = line.upper().strip()
@@ -165,9 +165,9 @@ def inp_in_energy(line: str) -> str:
                 if line.startswith('GLOBAL EFFICIENCY'):
                     value = line.removeprefix('GLOBAL EFFICIENCY').strip()
 
-                return f"update energy set value = '{value}' where key = '{key}';"
+                return str(f"update energy set value = '{value}' where key = '{key}';")
             
-    return ''
+    return str('')
 
 
 def inp_out_energy(name: str) -> list[str]:
diff --git a/api/s16_emitters.py b/api/s16_emitters.py
index 0bf06ad..8f510a9 100644
--- a/api/s16_emitters.py
+++ b/api/s16_emitters.py
@@ -78,7 +78,7 @@ def inp_in_emitter(line: str) -> str:
     junction = str(tokens[0])
     coefficient = float(tokens[1])
 
-    return f"insert into emitters (junction, coefficient) values ('{junction}', {coefficient});"
+    return str(f"insert into emitters (junction, coefficient) values ('{junction}', {coefficient});")
 
 
 def inp_out_emitter(name: str) -> list[str]:
diff --git a/api/s17_quality.py b/api/s17_quality.py
index 1087863..539b205 100644
--- a/api/s17_quality.py
+++ b/api/s17_quality.py
@@ -75,7 +75,7 @@ def inp_in_quality(line: str) -> str:
     node = str(tokens[0])
     quality = float(tokens[1])
 
-    return f"insert into quality (node, quality) values ('{node}', {quality});"
+    return str(f"insert into quality (node, quality) values ('{node}', {quality});")
 
 
 def inp_out_quality(name: str) -> list[str]:
diff --git a/api/s18_sources.py b/api/s18_sources.py
index 42cfb3f..0abaeda 100644
--- a/api/s18_sources.py
+++ b/api/s18_sources.py
@@ -121,8 +121,7 @@ def inp_in_source(line: str) -> str:
     pattern = str(tokens[3]) if num_without_desc >= 4 else None
     pattern = f"'{pattern}'" if pattern != None else 'null'
 
-    return f"insert into sources (node, s_type, strength, pattern) values ('{node}', '{s_type}', {strength}, {pattern});"
-
+    return str(f"insert into sources (node, s_type, strength, pattern) values ('{node}', '{s_type}', {strength}, {pattern});")
 
 
 def inp_out_source(name: str) -> list[str]:
diff --git a/api/s19_reactions.py b/api/s19_reactions.py
index 8ebf7a7..bf0faf5 100644
--- a/api/s19_reactions.py
+++ b/api/s19_reactions.py
@@ -201,21 +201,21 @@ def inp_in_reaction(line: str) -> str:
         pipe = tokens[1]
         key = token0.lower()
         value = tokens[2]
-        return f"insert into reactions_pipe_{key} (pipe, value) values ('{pipe}', {value});"
+        return str(f"insert into reactions_pipe_{key} (pipe, value) values ('{pipe}', {value});")
 
     elif token0 == 'TANK':
         tank = tokens[1]
         value = tokens[2]
-        return f"insert into reactions_tank (tank, value) values ('{tank}', {value});"
+        return str(f"insert into reactions_tank (tank, value) values ('{tank}', {value});")
 
     else:
         line = line.upper().strip()
         for key in get_reaction_schema('').keys():
             if line.startswith(key):
                 value = line.removeprefix(key).strip()
-                return f"update reactions set value = '{value}' where key = '{key}';"
+                return str(f"update reactions set value = '{value}' where key = '{key}';")
 
-    return ''
+    return str('')
 
 
 def inp_out_reaction(name: str) -> list[str]:
diff --git a/api/s1_title.py b/api/s1_title.py
index a038857..3ec5d6a 100644
--- a/api/s1_title.py
+++ b/api/s1_title.py
@@ -29,10 +29,10 @@ def set_title(name: str, cs: ChangeSet) -> ChangeSet:
 
 def inp_in_title(section: list[str]) -> str:
     if section == []:
-        return ''
+        return str('')
 
     title = '\n'.join(section)
-    return f"update title set value = '{title}';"
+    return str(f"update title set value = '{title}';")
 
 
 def inp_out_title(name: str) -> list[str]:
diff --git a/api/s20_mixing.py b/api/s20_mixing.py
index db4c8d3..5bef359 100644
--- a/api/s20_mixing.py
+++ b/api/s20_mixing.py
@@ -129,7 +129,7 @@ def inp_in_mixing(line: str) -> str:
     value = float(tokens[3]) if num_without_desc >= 4 else None
     value = value if value != None else 'null'
 
-    return f"insert into mixing (tank, model, value) values ('{tank}', '{model}', {value});"
+    return str(f"insert into mixing (tank, model, value) values ('{tank}', '{model}', {value});")
 
 
 def inp_out_mixing(name: str) -> list[str]:
diff --git a/api/s24_coordinates.py b/api/s24_coordinates.py
index 6c36216..bf313cf 100644
--- a/api/s24_coordinates.py
+++ b/api/s24_coordinates.py
@@ -3,16 +3,16 @@ from .database import *
 
 def sql_update_coord(node: str, x: float, y: float) -> str:
     coord = f"st_geomfromtext('point({x} {y})')"
-    return f"update coordinates set coord = {coord} where node = '{node}';"
+    return str(f"update coordinates set coord = {coord} where node = '{node}';")
 
 
 def sql_insert_coord(node: str, x: float, y: float) -> str:
     coord = f"st_geomfromtext('point({x} {y})')"
-    return f"insert into coordinates (node, coord) values ('{node}', {coord});"
+    return str(f"insert into coordinates (node, coord) values ('{node}', {coord});")
 
 
 def sql_delete_coord(node: str) -> str:
-    return f"delete from coordinates where node = '{node}';"
+    return str(f"delete from coordinates where node = '{node}';")
 
 
 def from_postgis_point(coord: str) -> dict[str, float]:
@@ -43,7 +43,7 @@ def inp_in_coord(line: str) -> str:
     tokens = line.split()
     node = tokens[0]
     coord = f"st_geomfromtext('point({tokens[1]} {tokens[2]})')"
-    return f"insert into coordinates (node, coord) values ('{node}', {coord});"
+    return str(f"insert into coordinates (node, coord) values ('{node}', {coord});")
 
 
 def inp_out_coord(name: str) -> list[str]:
diff --git a/api/s25_vertices.py b/api/s25_vertices.py
index 3660ce9..0bd7647 100644
--- a/api/s25_vertices.py
+++ b/api/s25_vertices.py
@@ -99,7 +99,7 @@ def inp_in_vertex(line: str) -> str:
     link = tokens[0]
     x = float(tokens[1])
     y = float(tokens[2])
-    return f"insert into vertices (link, x, y) values ('{link}', {x}, {y});"
+    return str(f"insert into vertices (link, x, y) values ('{link}', {x}, {y});")
 
 
 def inp_out_vertex(name: str) -> list[str]:
diff --git a/api/s26_labels.py b/api/s26_labels.py
index c7e7193..3bb0596 100644
--- a/api/s26_labels.py
+++ b/api/s26_labels.py
@@ -112,7 +112,7 @@ def inp_in_label(line: str) -> str:
     node = str(tokens[3]) if num >= 4 else None
     node = f"'{node}'" if node != None else 'null'
 
-    return f"insert into labels (x, y, label, node) values ({x}, {y}, '{label}', {node});"
+    return str(f"insert into labels (x, y, label, node) values ({x}, {y}, '{label}', {node});")
 
 
 def inp_out_label(name: str) -> list[str]:
diff --git a/api/s27_backdrop.py b/api/s27_backdrop.py
index 18f938a..bedc8fa 100644
--- a/api/s27_backdrop.py
+++ b/api/s27_backdrop.py
@@ -28,10 +28,10 @@ def set_backdrop(name: str, cs: ChangeSet) -> ChangeSet:
 
 def inp_in_backdrop(section: list[str]) -> str:
     if section == []:
-        return ''
+        return str('')
 
     content = '\n'.join(section)
-    return f"update backdrop set content = '{content}';"
+    return str(f"update backdrop set content = '{content}';")
 
 
 def inp_out_backdrop(name: str) -> list[str]:
diff --git a/api/s2_junctions.py b/api/s2_junctions.py
index 84164ea..723addb 100644
--- a/api/s2_junctions.py
+++ b/api/s2_junctions.py
@@ -158,7 +158,7 @@ def inp_in_junction(line: str, demand_outside: bool) -> str:
     if demand != None and demand_outside == False:
         sql += f"insert into demands (junction, demand, pattern) values ('{id}', {demand}, {pattern});"
 
-    return sql
+    return str(sql)
 
 
 def inp_out_junction(name: str) -> list[str]:
diff --git a/api/s32_region_util.py b/api/s32_region_util.py
index d95862b..4fdb46d 100644
--- a/api/s32_region_util.py
+++ b/api/s32_region_util.py
@@ -22,14 +22,14 @@ def to_postgis_polygon(boundary: list[tuple[float, float]]) -> str:
     polygon = ''
     for pt in boundary:
         polygon += f'{pt[0]} {pt[1]},'
-    return f'polygon(({polygon[:-1]}))'
+    return str(f'polygon(({polygon[:-1]}))')
 
 
 def to_postgis_linestring(boundary: list[tuple[float, float]]) -> str:
     line = ''
     for pt in boundary:
         line += f'{pt[0]} {pt[1]},'
-    return f'linestring({line[:-1]})'
+    return str(f'linestring({line[:-1]})')
 
 
 def get_nodes_in_boundary(name: str, boundary: list[tuple[float, float]]) -> list[str]:
diff --git a/api/s3_reservoirs.py b/api/s3_reservoirs.py
index 992b50b..b75630b 100644
--- a/api/s3_reservoirs.py
+++ b/api/s3_reservoirs.py
@@ -148,7 +148,7 @@ def inp_in_reservoir(line: str) -> str:
     pattern = f"'{pattern}'" if pattern != None else 'null'
     desc = str(tokens[-1]) if has_desc else None
 
-    return f"insert into _node (id, type) values ('{id}', 'reservoir');insert into reservoirs (id, head, pattern) values ('{id}', {head}, {pattern});"
+    return str(f"insert into _node (id, type) values ('{id}', 'reservoir');insert into reservoirs (id, head, pattern) values ('{id}', {head}, {pattern});")
 
 
 def inp_out_reservoir(name: str) -> list[str]:
diff --git a/api/s4_tanks.py b/api/s4_tanks.py
index 837c9af..ca47c1f 100644
--- a/api/s4_tanks.py
+++ b/api/s4_tanks.py
@@ -191,7 +191,7 @@ def inp_in_tank(line: str) -> str:
     overflow = f"'{overflow}'" if overflow != None else 'null'
     desc = str(tokens[-1]) if has_desc else None
 
-    return f"insert into _node (id, type) values ('{id}', 'tank');insert into tanks (id, elevation, init_level, min_level, max_level, diameter, min_vol, vol_curve, overflow) values ('{id}', {elevation}, {init_level}, {min_level}, {max_level}, {diameter}, {min_vol}, {vol_curve}, {overflow});"
+    return str(f"insert into _node (id, type) values ('{id}', 'tank');insert into tanks (id, elevation, init_level, min_level, max_level, diameter, min_vol, vol_curve, overflow) values ('{id}', {elevation}, {init_level}, {min_level}, {max_level}, {diameter}, {min_vol}, {vol_curve}, {overflow});")
 
 
 def inp_out_tank(name: str) -> list[str]:
diff --git a/api/s5_pipes.py b/api/s5_pipes.py
index 248e607..2a1499a 100644
--- a/api/s5_pipes.py
+++ b/api/s5_pipes.py
@@ -164,7 +164,7 @@ def inp_in_pipe(line: str) -> str:
     status = str(tokens[7].upper()) if num_without_desc >= 8 else PIPE_STATUS_OPEN
     desc = str(tokens[-1]) if has_desc else None
 
-    return f"insert into _link (id, type) values ('{id}', 'pipe');insert into pipes (id, node1, node2, length, diameter, roughness, minor_loss, status) values ('{id}', '{node1}', '{node2}', {length}, {diameter}, {roughness}, {minor_loss}, '{status}');"
+    return str(f"insert into _link (id, type) values ('{id}', 'pipe');insert into pipes (id, node1, node2, length, diameter, roughness, minor_loss, status) values ('{id}', '{node1}', '{node2}', {length}, {diameter}, {roughness}, {minor_loss}, '{status}');")
 
 
 def inp_out_pipe(name: str) -> list[str]:
diff --git a/api/s6_pumps.py b/api/s6_pumps.py
index d57a2c4..6bced9c 100644
--- a/api/s6_pumps.py
+++ b/api/s6_pumps.py
@@ -158,7 +158,7 @@ def inp_in_pump(line: str) -> str:
     pattern = f"'{pattern}'" if pattern != None else 'null'
     desc = str(tokens[-1]) if has_desc else None
 
-    return f"insert into _link (id, type) values ('{id}', 'pump');insert into pumps (id, node1, node2, power, head, speed, pattern) values ('{id}', '{node1}', '{node2}', {power}, {head}, {speed}, {pattern});"
+    return str(f"insert into _link (id, type) values ('{id}', 'pump');insert into pumps (id, node1, node2, power, head, speed, pattern) values ('{id}', '{node1}', '{node2}', {power}, {head}, {speed}, {pattern});")
 
 
 def inp_out_pump(name: str) -> list[str]:
diff --git a/api/s7_valves.py b/api/s7_valves.py
index 7268d47..e257740 100644
--- a/api/s7_valves.py
+++ b/api/s7_valves.py
@@ -160,7 +160,7 @@ def inp_in_valve(line: str) -> str:
     minor_loss = float(tokens[6]) if len(tokens) >= 7 else 0.0
     desc = str(tokens[-1]) if has_desc else None
 
-    return f"insert into _link (id, type) values ('{id}', 'valve');insert into valves (id, node1, node2, diameter, v_type, setting, minor_loss) values ('{id}', '{node1}', '{node2}', {diameter}, '{v_type}', '{setting}', {minor_loss});"
+    return str(f"insert into _link (id, type) values ('{id}', 'valve');insert into valves (id, node1, node2, diameter, v_type, setting, minor_loss) values ('{id}', '{node1}', '{node2}', {diameter}, '{v_type}', '{setting}', {minor_loss});")
 
 
 def inp_out_valve(name: str) -> list[str]:
diff --git a/api/s8_tags.py b/api/s8_tags.py
index 9f72610..32ad588 100644
--- a/api/s8_tags.py
+++ b/api/s8_tags.py
@@ -104,10 +104,10 @@ def inp_in_tag(line: str) -> str:
     tag = str(tokens[2])
 
     if t_type == TAG_TYPE_NODE:
-        return f"insert into tags_node (id, tag) values ('{id}', '{tag}');"
+        return str(f"insert into tags_node (id, tag) values ('{id}', '{tag}');")
     elif t_type == TAG_TYPE_LINK:
-        return f"insert into tags_link (id, tag) values ('{id}', '{tag}');"
-    return ''
+        return str(f"insert into tags_link (id, tag) values ('{id}', '{tag}');")
+    return str('')
 
 
 def inp_out_tag(name: str) -> list[str]:
diff --git a/api/s9_demands.py b/api/s9_demands.py
index de3de41..f53a5a1 100644
--- a/api/s9_demands.py
+++ b/api/s9_demands.py
@@ -79,7 +79,7 @@ def inp_in_demand(line: str) -> str:
     category = str(tokens[3]) if num_without_desc >= 4 else None
     category = f"'{category}'" if category != None else 'null'
 
-    return f"insert into demands (junction, demand, pattern, category) values ('{junction}', {demand}, {pattern}, {category});"
+    return str(f"insert into demands (junction, demand, pattern, category) values ('{junction}', {demand}, {pattern}, {category});")
 
 
 def inp_out_demand(name: str) -> list[str]:
diff --git a/build_pyd.py b/build_pyd.py
index 03e01de..ba50311 100644
--- a/build_pyd.py
+++ b/build_pyd.py
@@ -1,4 +1,8 @@
 from distutils.core import setup
 from Cython.Build import cythonize
 
-setup(ext_modules=cythonize("tjnetwork.py"))
\ No newline at end of file
+setup(ext_modules=cythonize([
+    "tjnetwork.py",
+    "api/*.py",
+    "epanet/*.py"
+    ]))
\ No newline at end of file