use package (module) with import

Still works...

import sys
import os

path = os.path.join( os.path.dirname(os.path.dirname(os.path.abspath(__file__))), '2' )
# print(path)
sys.path.insert(0, path)

import mymath.calc
print(mymath.calc.add(2, 5))  # 7

from mymath.calc import add
print(add(2, 3))              # 5