code: def _python_rpath(self):
          
          # Windows virtualenv installation installs pip to the [Ss]cripts
          # folder. Here's a simple check to support:
          if sys.platform == 'win32':
              return os.path.join('Scripts', 'python.exe')
          return os.path.join('bin', 'python')
docs: The relative path (from environment root) to python.