TypeError: method() takes 1 positional argument but 2 were given

Question

If I have a class...

class MyClass:

    def method(arg):
        print(arg)

...which I use to create an object...

my_objec         


        

Answer 1

Something else to consider when this type of error is encountered:

I was running into this error message and found this post helpful. Turns out in my case I had overridden an __init__() where there was object inheritance.

The inherited example is rather long, so I'll skip to a more simple example that doesn't use inheritance:

class MyBadInitClass:
    def ___init__(self, name):
        self.name = name

    def name_foo(self, arg):
        print(self)
        print(arg)
        print("My name is", self.name)


class MyNewClass:
    def new_foo(self, arg):
        print(self)
        print(arg)


my_new_object = MyNewClass()
my_new_object.new_foo("NewFoo")
my_bad_init_object = MyBadInitClass(name="Test Name")
my_bad_init_object.name_foo("name foo")

Result is:

<__main__.MyNewClass object at 0x033C48D0>
NewFoo
Traceback (most recent call last):
  File "C:/Users/Orange/PycharmProjects/Chapter9/bad_init_example.py", line 41, in 
    my_bad_init_object = MyBadInitClass(name="Test Name")
TypeError: object() takes no parameters

PyCharm didn't catch this typo. Nor did Notepad++ (other editors/IDE's might).

Granted, this is a "takes no parameters" TypeError, it isn't much different than "got two" when expecting one, in terms of object initialization in Python.

Addressing the topic: An overloading initializer will be used if syntactically correct, but if not it will be ignored and the built-in used instead. The object won't expect/handle this and the error is thrown.

In the case of the sytax error: The fix is simple, just edit the custom init statement:

def __init__(self, name):
    self.name = name