code: def pip_version(self):
          
          if not self._pip_exists:
              return None
          if not hasattr(self, '_pip_version'):
              # don't call `self._execute_pip` here as that method calls this one
              output = self._execute(self._pip + ['-V'], log=False).split()[1]
              self._pip_version = tuple([int(n) for n in output.split('.')])
          return self._pip_version
docs: Version of installed pip.