Validates an LSID with the LSID authority.
        :param lsid:
        :return: boolean - is the LSID valid with this authority?

def validate(self, lsid, check_existing=True):
        """
        Validates an LSID with the LSID authority.
        :param lsid:
        :return: boolean - is the LSID valid with this authority?
        """
        # Base LSID matches
        if not lsid.startswith(self.base_lsid):
            return False

        # Module number isn't already taken
        if check_existing and lsid in self.registered_modules:
            return False

        # Everything checks out, return True
        return True