@classmethod
def is_valid_packagename(cls, name):
    """
        Is this a valid package name?

        >>> PkgPolicy.is_valid_packagename('doesnotmatter')
        Traceback (most recent call last):
        ...
        NotImplementedError: Class needs to provide packagename_re
        """
    if cls.packagename_re is None:
        raise NotImplementedError('Class needs to provide packagename_re')
    return True if cls.packagename_re.match(name) else False
