title: How do I use scrapy in different versions of python
body: <p>I enter 'scrapy crawl PROJECT_NAME' in terminal and try to run a project coded with python2 but terminal tries to use scrapy in python3 and keeps reporting error(I have scrapy library for both python2/3). </p>
  
  <p>It could recognise python version of my project at first. But it fails to work now.</p>