def return_env(self, exists=True):
        """
        Return environment dict.

        Parameters
        ----------
        exists: bool
            It True, only return existing paths.

        Return
        ------
        dict
            environment
        """
        env = dict(
            include=self._build_paths(
                'include',
                [
                    self.VCIncludes,
                    self.OSIncludes,
                    self.UCRTIncludes,
                    self.NetFxSDKIncludes,
                ],
                exists,
            ),
            lib=self._build_paths(
                'lib',
                [
                    self.VCLibraries,
                    self.OSLibraries,
                    self.FxTools,
                    self.UCRTLibraries,
                    self.NetFxSDKLibraries,
                ],
                exists,
            ),
            libpath=self._build_paths(
                'libpath',
                [self.VCLibraries, self.FxTools, self.VCStoreRefs, self.OSLibpath],
                exists,
            ),
            path=self._build_paths(
                'path',
                [
                    self.VCTools,
                    self.VSTools,
                    self.VsTDb,
                    self.SdkTools,
                    self.SdkSetup,
                    self.FxTools,
                    self.MSBuild,
                    self.HTMLHelpWorkshop,
                    self.FSharp,
                ],
                exists,
            ),
        )
        if self.vs_ver >= 14 and isfile(self.VCRuntimeRedist):
            env['py_vcruntime_redist'] = self.VCRuntimeRedist
        return env

        Return environment dict.

        Parameters
        ----------
        exists: bool
            It True, only return existing paths.

        Return
        ------
        dict
            environment
        
product/gradle-plugin/src/main/python/setuptools/msvc.py