code: def roles_remove(user, role):
      
      user, role = _datastore._prepare_role_modify_args(user, role)
      if user is None:
          raise click.UsageError('Cannot find user.')
      if role is None:
          raise click.UsageError('Cannot find role.')
      if _datastore.remove_role_from_user(user, role):
          click.secho('Role "{0}" removed from user "{1}" '
                      'successfully.'.format(role, user), fg='green')
      else:
          raise click.UsageError('Cannot remove role from user.')
docs: Remove user from role.