Nested JSON Validation and Parsing

Question

I cannot return the nested JSON file after I validate it using Cerberus in my api. Validation works fine but I don't know how to input the JSON file to the "add_argument" function of RequestParser. I have defined the nested Json structure in a custom Validator Class. Since when all fields are Valid, it returns the Dictionary itself, its class is no longer the one I have defined which was "obs_validator". So defining my own structural class did not help me when I use add_argument. How can I resolve this issue?

def obs_validator(value):
    schema= {
      'input_item': {
          'type':'dict',
          'schema':{
        'type':{'type':'string', 'required': True},
        'id': {'type':'integer','required': True},
        'fields': { 'type': 'list', 'required': True, 'schema': 
                     { 'type': 'dict', 'schema': { 'field_name': {'type': 'string', 'required': True}, 
                                                  'field_text': {'type': 'string', 'required': True} 
                                                  } 
                     } 
                } 
        }
      },    
       'result_item_types': { 'type': 'list', 'required': True
                  
       },           
      'audit': {
          'type':'dict',
          'schema':{
            'audit_id': {'type':'integer', 'required': True},
            'audit_name': {'type':'string', 'required': True}
            }
      },
      'requested_by': {
          'type':'dict',
          'schema':{
            'GID': {'type':'string', 'required': True},
            'roles': {'type':'string', 'required': True}
            }
      },
      'authentication': {
          'type':'dict',
          'schema':{
            'checksum': {'type':'string', 'required': True},
            'validuntil': {'type':'string', 'required': True}
            }
      }
      
    }
        
    v =cerb.Validator(schema)
    if v.validate(value):
        return value
    else:
        raise ValueError(json.dumps(v.errors))

  
put_args = reqparse.RequestParser()
put_args.add_argument("What to write here??", type=obs_validator,action='append')


class text(Resource):
    
    def put(self):                  
          input_dict = put_args.parse_args()       
             return input_dict, 201