Python function parameter pass value or pass reference __ function

Keys = {"Status": True, ' name ': ' AAA '}

def fun1 (keys):
    print ' fun1 '
    print ' keys: ', keys
    print ' keys Address ", ID (keys)
    keys[' status ' = False

def fun2 (keys):
    print ' fun2 '
    print ' keys: ', keys
    print ' Keys address ", ID (keys)
    
fun1 (keys)
fun2 (keys)

#fun1
#keys: {' status ': True, ' name ': ' AAA '}
# Keys address 49248184

#fun2
#keys: {' status ': False, ' name ': ' AAA '}
#keys address 49248184

From the results above, the dictionary passed in a reference, within which the value could be changed.

Look at the string below

str1= ' Hello World '

def fun1 (str1):
    str1= "Ni hao"
    print "fun1 str1:", STR1, "ID:", ID (str1)

print " STR1: ", STR1," ID: ", ID (str1)
fun1 (str1)
print" str1: ", STR1," ID: ", ID (str1)

#str1: Hello World id:39530
#fun1 Str1:ni Hao id:40521600
#str1: Hello World id:39530000

From the above, the string does not change after the function call, but it changes inside the function. So the corresponding tuple, numeric constants, are not going to change.