code: def _verify_validator(self, validator, path):
          
  
          # Validator should be a function
          if not callable(validator):
              raise SchemaFormatException("Invalid validations for {}", path)
  
          # Validator should accept a single argument
          (args, varargs, keywords, defaults) = getargspec(validator)
          if len(args) != 1:
              raise SchemaFormatException("Invalid validations for {}", path)
docs: Verifies that a given validator associated with the field at the given path is legitimate.