Removes a role from a user.

        :param user: The user to manipulate
        :param role: The role to remove from the user

def remove_role_from_user(self, user, role):
        """Removes a role from a user.

        :param user: The user to manipulate
        :param role: The role to remove from the user
        """
        user, role = self._prepare_role_modify_args(user, role)
        result = self.UserRole.select().where(
            self.UserRole.user == user,
            self.UserRole.role == role,
        )
        if result.count():
            query = self.UserRole.delete().where(
                self.UserRole.user == user, self.UserRole.role == role)
            query.execute()
            return True
        else:
            return False