>>> client = Client('http://www.estes-express.com/shipmenttracking/services/ShipmentTrackingService?wsdl')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/lib/python2.7/site-packages/zeep/client.py", line 45, in __init__
    self.wsdl = WSDL(wsdl, self.transport)
  File "/lib/python2.7/site-packages/zeep/wsdl/wsdl.py", line 34, in __init__
    root_definitions = Definitions(self, document, self.location)
  File "/lib/python2.7/site-packages/zeep/wsdl/wsdl.py", line 106, in __init__
    self.schema = self.parse_types(doc)
  File "/lib/python2.7/site-packages/zeep/wsdl/wsdl.py", line 270, in parse_types
    self.wsdl._parser_context)
  File "/lib/python2.7/site-packages/zeep/xsd/schema.py", line 45, in __init__
    visitor.visit_schema(node)
  File "/lib/python2.7/site-packages/zeep/xsd/visitor.py", line 76, in visit_schema
    self.process(node, parent=parent)
  File "/lib/python2.7/site-packages/zeep/xsd/visitor.py", line 40, in process
    result = visit_func(self, node, parent)
  File "/lib/python2.7/site-packages/zeep/xsd/visitor.py", line 104, in visit_import
    schema_node, self.schema._transport, location, self.parser_context)
  File "/lib/python2.7/site-packages/zeep/xsd/schema.py", line 45, in __init__
    visitor.visit_schema(node)
  File "/lib/python2.7/site-packages/zeep/xsd/visitor.py", line 76, in visit_schema
    self.process(node, parent=parent)
  File "/lib/python2.7/site-packages/zeep/xsd/visitor.py", line 39, in process
    raise ValueError("No visitor defined for %r" % node.tag)
ValueError: No visitor defined for '{http://www.w3.org/2001/XMLSchema}include'