TypeError: Missing Required Positional Argument

Why This Happens

When a function defines parameters without default values, Python requires you to pass a value for each one. This commonly appears with class __init__ methods where you forget to pass constructor arguments.

The Problem

class User:
    def __init__(self, name, email):
        self.name = name
        self.email = email

user = User('Alice')

The Fix

class User:
    def __init__(self, name, email):
        self.name = name
        self.email = email

user = User('Alice', 'alice@example.com')

Step-by-Step Fix

1. 1

   Read the error message

   The error tells you exactly which argument is missing.

2. 2

   Check the function definition

   Review the parameter list to see what is required.

3. 3

   Add default values if appropriate

   Add a default: def __init__(self, name, email=None).