def function1():
print("function1")
def function2():
print("function2")
def function3():
print("function3")
def function4():
print("function4")
switch = {1:function1, 2:function2, 3:function3, 4:function4}
a = 1
switch.get(a, function1)()
switch.get(3, function1)()
'''
run:
function1
function3
'''