def remove(self, elem):
        """Remove a requirement.

        :param elem: a string or :class:`Requirement` instance.
        """
        if isinstance(elem, text_type):
            for requirement in self:
                if requirement.package == elem:
                    return super(Requirements, self).remove(requirement)
        return super(Requirements, self).remove(elem)
def exceptions_log_path(cls, for_pid=None, in_dir=None):
        """Get the path to either the shared or pid-specific fatal errors log file."""
        if for_pid is None:
            intermediate_filename_component = ""
        else:
            assert isinstance(for_pid, Pid)
            intermediate_filename_component = ".{}".format(for_pid)
        in_dir = in_dir or cls._log_dir
        return os.path.join(
            in_dir, ".pids", "exceptions{}.log".format(intermediate_filename_component)
        )