Fix service area case

dev.py

@@ -0,0 +1,11 @@
+from tjnetwork import *
+
+p = 'dev'
+read_inp(p, './inp/net3.inp', '3')
+
+open_project(p)
+
+sass = calculate_service_area(p)
+assert len(sass) == 25
+print(sass[0])
+print(sass[1])