https://bugs.python.org/review/28977/diff/19473/Doc/c-api/object.rst File Doc/c-api/object.rst (right): https://bugs.python.org/review/28977/diff/19473/Doc/c-api/object.rst#newcode... Doc/c-api/object.rst:279: there is a single argument. PyObject_CallFunctionObjArgs looks better alternative to me. And PyObject_CallObject is better alternative when you need to unpack a tuple. Since "O" is exceptional case and its behavior is likely unexpected, and there are good alternatives, maybe format this note with "note" or "warning" directives? https://bugs.python.org/review/28977/