code: func (r *Role) Check() error {
  	switch *r {
  	case RoleAuth, RoleWeb, RoleNode,
  		RoleAdmin, RoleProvisionToken,
  		RoleTrustedCluster, LegacyClusterTokenType,
  		RoleSignup, RoleProxy, RoleNop:
  		return nil
  	}
  	return trace.BadParameter("role %v is not registered", *r)
  }
docs: // Check checks if this a a valid role value, returns nil
  // if it's ok, false otherwise