How to change python launch command in PyCharm

How to change python launch command in PyCharm

If I directly run start.py, I get:
Symbol not found: _OCIAttrGet
Referenced from: /Library/Python/2.7/site-packages/cx_Oracle.so
After some googling, I found that its because Oracle client arch issues. I
now run my script like this and it works:
arch -i386 python2.7 start.py
Now with a free edition of PyCharm available (thank you JetBrains), I
imported my projects but how do I set the "Run Configuration" to launch my
script the way I do it from terminal.
I tried:
Run -> Edit Configuration -> Python Interpreter but it is already
populated with the known python paths
Run -> Edit Configuration -> Interpreter Options but throws an error
saying unknown file "arch"
Any workarounds?