Samples: Fix avro.schema.Parse in snippets (#888)

* fix avro.schema.parse in snippets

* fix all

* change avro.schema to schema

* change revert Parse

samples/snippets/schema.py

@@ -457,7 +457,7 @@ def publish_avro_records(project_id: str, topic_id: str, avsc_file: str) -> None
     """Pulbish a BINARY or JSON encoded message to a topic configured with an Avro schema."""
     # [START pubsub_publish_avro_records]
     from avro.io import BinaryEncoder, DatumWriter
-    import avro
+    import avro.schema as schema
     import io
     import json
     from google.api_core.exceptions import NotFound
@@ -473,7 +473,7 @@ def publish_avro_records(project_id: str, topic_id: str, avsc_file: str) -> None
     topic_path = publisher_client.topic_path(project_id, topic_id)
 
     # Prepare to write Avro records to the binary output stream.
-    avro_schema = avro.schema.parse(open(avsc_file, "rb").read())
+    avro_schema = schema.parse(open(avsc_file, "rb").read())
     writer = DatumWriter(avro_schema)
     bout = io.BytesIO()
 
@@ -562,7 +562,7 @@ def subscribe_with_avro_schema(
 ) -> None:
     """Receive and decode messages sent to a topic with an Avro schema."""
     # [START pubsub_subscribe_avro_records]
-    import avro
+    import avro.schema as schema
     from avro.io import BinaryDecoder, DatumReader
     from concurrent.futures import TimeoutError
     import io
@@ -579,7 +579,7 @@ def subscribe_with_avro_schema(
     subscriber = SubscriberClient()
     subscription_path = subscriber.subscription_path(project_id, subscription_id)
 
-    avro_schema = avro.schema.parse(open(avsc_file, "rb").read())
+    avro_schema = schema.parse(open(avsc_file, "rb").read())
 
     def callback(message: pubsub_v1.subscriber.message.Message) -> None:
         # Get the message serialization type.
@@ -622,7 +622,7 @@ def subscribe_with_avro_schema_with_revisions(
 ) -> None:
     """Receive and decode messages sent to a topic with an Avro schema."""
     # [START pubsub_subscribe_avro_records_with_revisions]
-    import avro
+    import avro.schema as schema
     from avro.io import BinaryDecoder, DatumReader
     from concurrent.futures import TimeoutError
     import io
@@ -642,7 +642,7 @@ def subscribe_with_avro_schema_with_revisions(
     subscriber = SubscriberClient()
     subscription_path = subscriber.subscription_path(project_id, subscription_id)
 
-    writer_avro_schema = avro.schema.parse(open(avsc_file, "rb").read())
+    writer_avro_schema = schema.parse(open(avsc_file, "rb").read())
     # Dict to keep readers for different schema revisions.
     revisions_to_readers = {}
 
@@ -662,7 +662,7 @@ def callback(message: pubsub_v1.subscriber.message.Message) -> None:
                 print(f"{schema_path} not found.")
                 message.nack()
                 return
-            reader_avro_schema = avro.schema.parse(received_avro_schema.definition)
+            reader_avro_schema = schema.parse(received_avro_schema.definition)
             revisions_to_readers[schema_revision_id] = DatumReader(
                 writer_avro_schema, reader_avro_schema
             )