Add more shard iterator types.

moto/kinesis/exceptions.py

@@ -17,3 +17,18 @@ class StreamNotFoundError(ResourceNotFoundError):
     def __init__(self, stream_name):
         super(StreamNotFoundError, self).__init__(
             'Stream {0} under account 123456789012 not found.'.format(stream_name))
+
+
+class ShardNotFoundError(ResourceNotFoundError):
+    def __init__(self, shard_id):
+        super(ShardNotFoundError, self).__init__(
+            'Shard {0} under account 123456789012 not found.'.format(shard_id))
+
+
+class InvalidArgumentError(BadRequest):
+    def __init__(self, message):
+        super(InvalidArgumentError, self).__init__()
+        self.description = json.dumps({
+            "message": message,
+            '__type': 'InvalidArgumentException',
+        })