How do I properly import/use classes and modules I built in Python in other classes/modules?

Question

I am moving from a functional approach to a more object oriented approach for building a library of valuation models for (derivative) financial instruments in Python. I keep getting error messages that I do not understand.

Let me first explain what I am doing:

I create a class where I define and store the common attributes of the product for which I am building a valuation model. As an example, let’s work with the class Option:
```
class Option(object):
  def _init_ (self, S0, ..., params):
       self.So = S0
       ...
       self.div = params.get('div',0)
       ...
```

I then build a class for the valuation of the option (let’s work with a binomial model)

from Option import Option

class BinomialOption(Option):    
    def _setup_parameters_(self):
        self.X = ...
        ........

When I do this, get an import error:

ImportError: No module named 'Option'

I do not understand why this happens. I created a class, and I ran it before running the BinomialOption class.

Why do I get this error message? And how do I prevent it?

possible answer in http://stackoverflow.com/questions/2349991/python-how-to-import-other-python-files — 0xtvarun, Nov 16 '15 at 08:24
Where is Option defined? Is it in a file called Option.py? Is that file on your Python path, or in the same directory as the one that defines BinomialOption? — Daniel Roseman, Nov 16 '15 at 08:27

score 0 · Accepted Answer · edited May 23 '17 at 12:15

0

Let me guess, you have a directory for libs and other directory for the programs, haven't you? If that's the case, you have a problem with your path.

In StackOverflow you have already similar questions with the answer:

edited May 23 '17 at 12:15

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answered Nov 16 '15 at 09:07

How do I properly import/use classes and modules I built in Python in other classes/modules?

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