How can I mock an attribute of a function so that it returns an integer rather than a MagicMock object?

Question

I am working with the following code and test, which live in separate files:

#exchange.py
def on_indicative_price_volume(self, msg):
    symbol = self.get_symbol(msg.security_id)
    breakpoint()
    price = msg.pre_open_price * symbol.deal_price_multiplier
    self.write_auc(msg.security_id)


#test.py
@mock.patch('exchange.IceExchange.get_symbol')
def test_indicative_price_and_vol(mock_symbol, exchange):    
    mock_symbol.deal_price_multiplier = 25

So in my unit test, I have mocked out the functionget_symbol. So that when I print symbol where I set the breakpoint above, I get:

 <MagicMock name='get_symbol().deal_price_multiplier.__rmul__()' id='14032624'>

So it has been mocked as expected. But now I want to set symbol.deal_price_multiplier in my function to return the value 25.

As you can see above in my unit test I tried to do mock_symbol.deal_price_multiplier = 25, but when I print symbol.deal_price_multiplier in my function I then get:

<MagicMock name='get_symbol().deal_price_multiplier.__rmul__()' id='14424'>

Which is not what I want, I want mock_symbol.deal_price_multiplier to simply return 25. How can I do this?