def to_xml(self, xml_parent):
    limit = SubElement(xml_parent, 'limit')
    limit.set('velocity', str(self.velocity))
    limit.set('effort', str(self.effort))
    limit.set('lower', str(self.lower))
    limit.set('upper', str(self.upper))
    return limit
def to_xml(self, xml_parent):
    limit = SubElement(xml_parent, 'limit')
    limit.set('velocity', str(self.velocity))
    limit.set('effort', str(self.effort))
    limit.set('lower', str(self.lower))
    limit.set('upper', str(self.upper))
    return limit