@workdir_loaded<EOL><INDENT>def set_current(self, new_current):<DEDENT>
self._set_current(new_current)<EOL>
Change the current default prefix

Args:
    new_current(str): Name of the new current prefix, it must already
        exist

Returns:
    None

Raises:
    PrefixNotFound: if the given prefix name does not exist in the
        workdir