code: def get_children_max(children, attr, root):
      return max([root[childId]["meta"][attr] for childId in children])
  
imports: import collections
  import json
  import sys
  import uuid
  from functools import reduce
  from alembic import op
  from sqlalchemy import Column, ForeignKey, Integer, String, Table, Text
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy.orm import relationship
  from superset import db
label_desc: Use image node_id 10 for calling a global function with example usage: get_children_max(children, attr, root) and returns: max