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 reset_should_print_backtrace_to_terminal(cls, should_print_backtrace):
        """Set whether a backtrace gets printed to the terminal error stream on a fatal error.

        Class state:
        - Overwrites `cls._should_print_backtrace_to_terminal`.
        """
        cls._should_print_backtrace_to_terminal = should_print_backtrace