Reports when a type that doesn't define __str__, __repr__, or __format__ is converted to a string. The default string representation may not be useful for debugging or display purposes.

Example:

class A:
    pass

str(A())  # Result: "<__main__.A object at 0x...>"

Consider defining one of these methods to provide a meaningful string representation:

class A:
    def __str__(self):
        return "A instance"
    
    def __repr__(self):
        return "A()"