Fix three code bugs

src/zeep/cache.py

@@ -24,10 +24,10 @@
 class Base(object):
 
     def add(self, url, content):
-        raise NotImplemented()
+        raise NotImplementedError()
 
     def get(self, url):
-        raise NotImplemented()
+        raise NotImplementedError()
 
 
 class InMemoryCache(Base):
@@ -131,6 +131,8 @@ def _decode_data(self, data):
             data = str(data)
         if data.startswith(self._version_string):
             return base64.b64decode(data[len(self._version_string):])
+        # Return None for invalid/incompatible cache data
+        return None
 
     @property
     def _version_string(self):

src/zeep/client.py

@@ -183,6 +183,8 @@ def _get_port(self, service, name):
             if not port:
                 raise ValueError("Port not found")
         else:
+            if not service.ports:
+                raise ValueError("No ports available in service")
             port = list(service.ports.values())[0]
         return port
 

src/zeep/helpers.py

@@ -59,12 +59,14 @@ def create_xml_soap_map(values):
 
 def guess_xsd_type(obj):
     """Return the XSD Type for the given object"""
+    # Check bool before int since bool is a subclass of int in Python
     if isinstance(obj, bool):
         return xsd.Boolean()
     if isinstance(obj, int):
         return xsd.Integer()
     if isinstance(obj, float):
         return xsd.Float()
+    # Check datetime before date since datetime is a subclass of date
     if isinstance(obj, datetime.datetime):
         return xsd.DateTime()
     if isinstance(obj, datetime.date):