python is argument by copy or refernece code example

Example: python pass by reference

# objects are passed by reference, but
# its references are passed by value

myList = ['foo', 'bar']

def modifyList(l):
  l.append('qux') # modifies the reference
  l = ['spam', 'eggs'] # replaces the reference
  l.append('lol') # modifies the new reference

modifiyList(myList)

print(myList) # ['foo', 'bar', 'qux']