code: def validate_color(self, _, color):
      # TODO: [AT] add color validation
      return color
  
imports: from sqlalchemy import Boolean, Column, DateTime, ForeignKey, Integer, Table, Text
  from sqlalchemy.orm import relationship, backref, validates
  from sqlalchemy.ext.declarative import declarative_base
  import uuid
  import datetime
label_desc: Use image node_id 2 for calling the Tag obj's underlying member method code with example usage: obj.validate_color(_, color) and returns: color