Pylint: Disable Unnecessary "else" after "return" (no-else-return) warning

You are looking for no-else-return (R1705). Just add these to your .pylintrc:

[REFACTORING]
no-else-return=no

In this particular case you could be better off using a ternary operator.

def is_positive(number):
    return "+++" if number > 0 else "---"

You should add no-else-return to the comma separated list of disabled options in the disable setting in your .pylintrc file.

Also see the Pylint docs:
http://pylint.pycqa.org/en/latest/technical_reference/features.html#messages-control-options