Python generate data based on archives

I'm working on a operations research project.

I created a heuristic method and I need to test my method intensively to assess its performance.

I have the past data, in form of 3 fields;

Date, Amount, Type

What I want is to generate new data, similar to the the existing data. I'm currently doing this with "+/- random".

I there a method or lib to generate original data, similar to the existing data by analysing statistics and trends of the old data.