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 display(self, callingWindow, srcContext, mainItem):
        if srcContext not in ("marketItemGroup", "marketItemMisc") or self.mainFrame.getActiveFit() is None:
            return False

        if mainItem is None:
            return False

        for attr in ("emDamage", "thermalDamage", "explosiveDamage", "kineticDamage"):
            if mainItem.getAttribute(attr) is not None:
                return True

        return False