Python父目录、子目录的相互调用方法

def showdata():
  print("this is a")

def plus():
  a=1
  b=2
  print(a+b)

def show():
  print("this is b")

from test1.a import showdata
from test1.a import plus
from test2.b import show

showdata()
show()
plus()

import sys

sys.path.append("..")
from test1 import a as t

t.showdata()