code: def clean_pair(cls, attribute, value):
      '''
      This will call `clean_attribute` on the attribute and also allows for the
      creation of boolean attributes.
  
      Ex. input(selected=True) is equivalent to input(selected="selected")
      '''
      attribute = cls.clean_attribute(attribute)
  
      # Check for boolean attributes
      # (i.e. selected=True becomes selected="selected")
      if value is True:
        value = attribute
  
      if value is False:
        value = "false"
  
      return (attribute, valuef clean_pair(cls, attribute, value):
      '''
      This will call `clean_attribute` on the attribute and also allows for the
      creation of boolean attributes.
  
      Ex. input(selected=True) is equivalent to input(selected="selected")
      '''
      attribute = cls.clean_attribute(attribute)
  
      # Check for boolean attributes
      # (i.e. selected=True becomes selected="selected")
      if value is True:
        value = attribute
  
      if value is False:
        value = "false"
  
      return (attribute, value)
docs: This will call `clean_attribute` on the attribute and also allows for the
      creation of boolean attributes.
  
      Ex. input(selected=True) is equivalent to input(selected="selected")