def call_vcs_version(self):
        # type: () -> Tuple[int, ...]
        """Query the version of the currently installed Subversion client.

        :return: A tuple containing the parts of the version information or
            ``()`` if the version returned from ``svn`` could not be parsed.
        :raises: BadCommand: If ``svn`` is not installed.
        """
        # Example versions:
        #   svn, version 1.10.3 (r1842928)
        #      compiled Feb 25 2019, 14:20:39 on x86_64-apple-darwin17.0.0
        #   svn, version 1.7.14 (r1542130)
        #      compiled Mar 28 2018, 08:49:13 on x86_64-pc-linux-gnu
        version_prefix = 'svn, version '
        version = self.run_command(['--version'], show_stdout=False)
        if not version.startswith(version_prefix):
            return ()

        version = version[len(version_prefix):].split()[0]
        version_list = version.split('.')
        try:
            parsed_version = tuple(map(int, version_list))
        except ValueError:
            return ()

        return parsed_version
Query the version of the currently installed Subversion client.

        :return: A tuple containing the parts of the version information or
            ``()`` if the version returned from ``svn`` could not be parsed.
        :raises: BadCommand: If ``svn`` is not installed.
        
product/gradle-plugin/src/main/python/pip/_internal/vcs/subversion.py