class_docstr: A string holding a valid HTML color such as 'blue', '#060482', '#A80'
code: def validate(self, obj, value):
      if value is None and self.allow_none:
          return value
      if isinstance(value, string_types):
          if (
              value.lower() in _color_names
              or _color_hex_re.match(value)
              or _color_hexa_re.match(value)
              or _color_rgbhsl_re.match(value)
          ):
              return value
  
      self.error(obj, value)
  
imports: import re
  import traitlets
  import datetime
  from .util import string_types
label_desc: Use image node_id 1 for calling the Color obj's underlying member method code with example usage: obj.validate(obj, value) and returns: value, value