'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):

    (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
