IndentationError: unindent does not match any outer indentation level

Question

When I compile the Python code below, I get

IndentationError: unindent does not match any outer indentation level

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Answer 1

For SPYDER users: I'm using spyder 3.3.2 with python 3.7.1 and I solved this, setting indentation to use tabs, with the following steps, click on:

• Tools.
• Preferences.
• Editor.
• Advanced settings.
• Indentation characters -> Tabs.

Then I reset the "unidented" line using tab key.

For some reason, without this setting, I got the ghost IndentationError sometimes.