def sanitizer(unit):
    """
    Sanitizes a unit string. That is, it is de-blanked, and mu and µ symbols
    are changed to u for micro.

    :param unit: The unit that needs to be sanitized.

    :returns: the sanitized unit.
    :rtype: str
    """
    micro = 'µ'
    mugr = 'μ'
    return unit.replace(' ', '').replace('mu', 'u').replace(micro, 'u'
        ).replace(mugr, 'u')
