def read(*parts):
    """
    Build an absolute path from *parts* and and return the contents of the
    resulting file.  Assume UTF-8 encoding.
    """
    with codecs.open(os.path.join(HERE, *parts), "rb", "utf-8") as f:
        return f.read()
def switch(self, dest, url, rev_options):
        # type: (str, HiddenText, RevOptions) -> None
        self.run_command(
            make_command('config', 'remote.origin.url', url),
            cwd=dest,
        )
        cmd_args = make_command('checkout', '-q', rev_options.to_args())
        self.run_command(cmd_args, cwd=dest)

        self.update_submodules(dest)