TypeError: can only concatenate str (not 'int') to str

The error occurred because you attempted to combine a string and an integer using the '+' operator. In Python, you can only concatenate strings with other strings.

This broke because Python does not automatically convert integers to strings during concatenation. The operation requires both operands to be of the same type.

To fix this error, convert the integer to a string using the `str()` function before concatenation. This ensures both operands are strings.