code: def clean(file_, imports):
      
      modules_not_imported = compare_modules(file_, imports)
      re_remove = re.compile("|".join(modules_not_imported))
      to_write = []
  
      try:
          f = open_func(file_, "r+")
      except OSError:
          logging.error("Failed on file: {}".format(file_))
          raise
      else:
          for i in f.readlines():
              if re_remove.match(i) is None:
                  to_write.append(i)
          f.seek(0)
          f.truncate()
  
          for i in to_write:
              f.write(i)
      finally:
          f.close()
  
      logging.info("Successfully cleaned up requirements in " + file_)
docs: Remove modules that aren't imported in project from file.