code: def _finalize_requires(self):
          
          if getattr(self, 'python_requires', None):
              self.metadata.python_requires = self.python_requires
  
          if getattr(self, 'extras_require', None):
              for extra in self.extras_require.keys():
                  # Since this gets called multiple times at points where the
                  # keys have become 'converted' extras, ensure that we are only
                  # truly adding extras we haven't seen before here.
                  extra = extra.split(':')[0]
                  if extra:
                      self.metadata.provides_extras.add(extra)
  
          self._convert_extras_requirements()
          self._move_install_requirements_markers()
docs: Set `metadata.python_requires` and fix environment markers
          in `install_requires` and `extras_require`.