Cannot marshal <class 'decimal.Decimal'> objects

[Skip Montanaro]

> I am getting this error.

I assume you mean the email subject. It doesn't work in 3.8 either:

>>> import decimal
>>> d = decimal.Decimal(3.5)
>>> d
Decimal('3.5')
>>> import marshal
>>> marshal.dumps(d)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: unmarshallable object

but that's not surprising to me. The marshal module is more-or-less
meant to serialize Python byte code. Pickle is more generally used for
object serialization. Why not use it?

>>> import pickle, decimal
>>> d = decimal.Decimal(3.5)
>>> pickle.dumps(d)
b'\x80\x04\x95!\x00\x00\x00\x00\x00\x00\x00\x8c\x07decimal\x94\x8c\x07Decimal\x94\x93\x94\x8c\x033.5\x94\x85\x94R\x94.'

That's meant more for serialization of data objects.

Skip