When you define an assert statement to test a tuple the test will either always succeed (if the tuple is non-empty) or always fail (if the tuple is empty).

This error usually occurs when the programmer writes assert (condition, message) instead of the correct form assert condition, message

Review the code and determine the purpose of the assert statement:

The statement assert (xxx, yyy) attempts to test a "tuple" (xxx, yyy). The original intention may be any of the alternatives listed below:

If you want to define a validity check on the values of a tuple then these must be tested individually.

  • Python Language Reference: The assert statement.
  • Tutorials Point: Assertions in Python.