code: def validate_fixed(datum, schema, **kwargs):
      
      return (
              (isinstance(datum, bytes) and len(datum) == schema['size'])
              or (isinstance(datum, decimal.Decimal))
      )
docs: Check that the data value is fixed width bytes,
      matching the schema['size'] exactly!
  
      Parameters
      ----------
      datum: Any
          Data being validated
      schema: dict
          Schema
      kwargs: Any
          Unused kwargs