Adding type info to Converter interface.

Signed-off-by: Evan Anderson <argent@google.com>

cloudevents/sdk/converters/base.py

@@ -25,10 +25,10 @@ class Converter(object):
              data_unmarshaller: typing.Callable) -> base.BaseEvent:
         raise Exception("not implemented")
 
-    def event_supported(self, event):
+    def event_supported(self, event: object) -> bool:
         raise Exception("not implemented")
 
-    def can_read(self, content_type):
+    def can_read(self, content_type: str) -> bool:
         raise Exception("not implemented")
 
     def write(self, event: base.BaseEvent,

cloudevents/sdk/converters/binary.py

@@ -25,10 +25,10 @@ class BinaryHTTPCloudEventConverter(base.Converter):
     TYPE = "binary"
     SUPPORTED_VERSIONS = [v02.Event, ]
 
-    def can_read(self, content_type):
+    def can_read(self, content_type: str) -> bool:
         return True
 
-    def event_supported(self, event):
+    def event_supported(self, event: object) -> bool:
         return type(event) in self.SUPPORTED_VERSIONS
 
     def read(self,

cloudevents/sdk/converters/structured.py

@@ -23,10 +23,10 @@ class JSONHTTPCloudEventConverter(base.Converter):
     TYPE = "structured"
     MIME_TYPE = "application/cloudevents+json"
 
-    def can_read(self, content_type):
+    def can_read(self, content_type: str) -> bool:
         return content_type and content_type.startswith(self.MIME_TYPE)
 
-    def event_supported(self, event):
+    def event_supported(self, event: object) -> bool:
         # structured format supported by both spec 0.1 and 0.2
         return True