python is a strictly dependent indentation language, if not properly indented or indented format is not unified, general error message will clearly tell you, but sometimes appears invalid syntax error.
The so-called indentation is not correct, python indentation is four spaces or a TAB, if indented three spaces, some being given
so-called indentation, that is not a space and TAB mix. If it is unclear whether there is a mix, you can use the sublime unity adjusted.
