TypeError: f() missing 1 required positional argument: 'x'
A function was called without a required parameter.
Seen on:
Python
Meaning
Common when calling an instance method on the class instead of an instance (Class.method()), when a framework calls your callback with fewer arguments, or after adding a new parameter.
Common causes
- Calling a method on the class instead of an instance
- New required parameter not passed by callers
- Dataclass/pydantic field without default
⚡ Quick fix
- Create an instance first: Api().get(path)
- Give new parameters defaults
- Pass the argument by name
Detailed fix by platform
Python
- Use keyword arguments for clarity: create_user(email=email, name=name)
How to diagnose
- Parameter — Which one is missing?
- Caller — Class or instance call?
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Last updated 2 Oct 2026