Fixed bugs and added factorial function

[sbrietzke]

No description provided.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@0f001e7). Click here to learn what that means.
The diff coverage is 66.66%.

@@            Coverage Diff            @@
##             master      #10   +/-   ##
=========================================
  Coverage          ?   66.66%           
=========================================
  Files             ?        1           
  Lines             ?       12           
  Branches          ?        2           
=========================================
  Hits              ?        8           
  Misses            ?        3           
  Partials          ?        1

Impacted Files	Coverage Δ
factorial.py	66.66% <66.66%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0f001e7...8506eaa. Read the comment docs.