c2.py

from c1 import *
#accessing variable names having single leading underscore.
print (_a)#Output:NameError: name '_a' is not defined


#accessing function name havig single leading underscore
print (_sub(7,2))#Output:NameError: name '_sub' is not defined


#accessing variables and functions which is not having single leading underscore.
# we will able to access those varaibles and functions
add(3,4)#Output:7
print (b)#helloworld