title: send argument in gitlab-ci to a python project
body: <p>Recently I created a project and dockerize it.
  in order to write a <strong>.gitlab-ci.yml</strong>, I want to prepare a test stage to test my program.</p>
  
  <p>in the middle of my python code, I ask from the user a username and password,
  but because in the gitlab-ci, everything should be executed automatically, I want to send username and password inside my gitlab-ci instead of reading from the input.
  how can I send a username and password which is a static phrase to my python code inside of my gitlab-ci?</p>
  
  <p><strong>Please pay attention that I don't want to use sys.args in my python code, because in real execution I want to read it from user really, but just in gitlab-ci, I want to send a specific username and password to that program so it can execute automatically.</strong></p>