      child = None
      many = True
  
      default_error_messages = {
          'not_a_list': _("Expected a list of items but got type `{input_type}`.")
      }
  
      def __init__(self, *args, **kwargs):
          self.child = kwargs.pop('child', copy.deepcopy(self.child))
          assert self.child is not None, '`child` is a required argument.'
 
</s> remove         'invalid': _("Invalid data. Expected a dictionary, but got {datatype}.")
 </s> add         'invalid': _('Invalid data. Expected a dictionary, but got {datatype}.') </s> remove         'does_not_exist': _("Object with {slug_name}={value} does not exist."),
        'invalid': _("Invalid value."),
 </s> add         'does_not_exist': _('Object with {slug_name}={value} does not exist.'),
        'invalid': _('Invalid value.'), </s> remove         'invalid': _("Enter a valid email address.")
 </s> add         'invalid': _('Enter a valid email address.') </s> remove         'slug 99': ["Enter a valid 'slug' consisting of letters, numbers, underscores or hyphens."]
 </s> add         'slug 99': ['Enter a valid "slug" consisting of letters, numbers, underscores or hyphens.'] </s> remove         'invalid': _("`{input}` is not a valid boolean.")
 </s> add         'invalid': _('`{input}` is not a valid boolean.')
        'not_a_list': _('Expected a list of items but got type `{input_type}`.')
      child = None
      many = True
  
      default_error_messages = {
        'not_a_list': _('Expected a list of items but got type `{input_type}`.')
      }
  
      def __init__(self, *args, **kwargs):
          self.child = kwargs.pop('child', copy.deepcopy(self.child))
          assert self.child is not None, '`child` is a required argument.'
keep keep keep keep replace keep keep keep keep keep
 prefer single quotes in source and double quotes in user visible strings; add some missing full stops to user visible strings 
rest_framework/serializers.py