code: def get_vcenter(self, **kwargs):
          
          config = ET.Element("config")
          urn = "urn:brocade.com:mgmt:brocade-vswitch"
          ET.SubElement(config, "vcenter", xmlns=urn)
          output = self._callback(config, handler='get_config')
          result = []
          element = ET.fromstring(str(output))
          for vcenter in element.iter('{%s}vcenter'%urn):
              vc = {}
              vc['name'] = vcenter.find('{%s}id' % urn).text
              vc['url'] = (vcenter.find('{%s}credentials' % urn)).find('{%s}url' % urn).text
              isactive = vcenter.find('{%s}activate' %urn)
              if isactive is None:
                  vc['isactive'] = False
              else:
                  vc['isactive'] = True
              result.append(vc)
          return result
docs: Get vCenter hosts on the switch
  
          Args:
  
              callback (function): A function executed upon completion of the
                   method.
  
          Returns:
             Returns a list of vcenters
  
          Raises:
              None