python type_error ai_generated true

TypeError: function() missing 1 required positional argument

ID: python/typeerror-missing-argument

Also available as: JSON · Markdown
95%Fix Rate
95%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
311 active — — —

Root Cause

Function called with wrong number of args. Common after refactoring or missing self.

generic

Workarounds

  1. 95% success Check if calling instance method without self, or missing args after refactor 
    Check if calling instance method without self, or missing args after refactor

    Sources: https://docs.python.org/3/tutorial/classes.html#method-objects

  2. 92% success Compare call site args with function signature 
    import inspect
print(inspect.signature(my_function))  # Shows expected params
# Then compare with how you're calling it

    Sources: https://docs.python.org/3/library/inspect.html#inspect.signature

Dead Ends

Common approaches that don't work:

  1. Add default=None to all params 65% fail

    Hides the real issue — caller should provide the value

  2. Use *args/**kwargs to accept anything 75% fail

    Loses function signature, makes bugs harder to find

Error Chain

Preceded by: