docs(bigquery): consistent use of optional keyword (#153)

* docs(bigquery): consistent use of optional keyword * docs(bigquery): nit

Author: HemangChothani

google/cloud/bigquery/_helpers.py

@@ -471,16 +471,16 @@ def _get_sub_prop(container, keys, default=None):
 
  This method works like ``dict.get(key)``, but for nested values.
 
- Arguments:
+ Args:
  container (Dict):
  A dictionary which may contain other dictionaries as values.
  keys (Iterable):
  A sequence of keys to attempt to get the value for. Each item in
  the sequence represents a deeper nesting. The first key is for
  the top level. If there is a dictionary there, the second key
  attempts to get the value within that, and so on.
- default (object):
- (Optional) Value to returned if any of the keys are not found.
+ default (Optional[object]):
+ Value to returned if any of the keys are not found.
  Defaults to ``None``.
 
  Examples:
@@ -514,7 +514,7 @@ def _get_sub_prop(container, keys, default=None):
 def _set_sub_prop(container, keys, value):
  """Set a nested value in a dictionary.
 
- Arguments:
+ Args:
  container (Dict):
  A dictionary which may contain other dictionaries as values.
  keys (Iterable):
@@ -557,7 +557,7 @@ def _set_sub_prop(container, keys, value):
 def _del_sub_prop(container, keys):
  """Remove a nested key fro a dictionary.
 
- Arguments:
+ Args:
  container (Dict):
  A dictionary which may contain other dictionaries as values.
  keys (Iterable):

google/cloud/bigquery/_http.py

@@ -25,7 +25,7 @@ class Connection(_http.JSONConnection):
  Args:
  client (google.cloud.bigquery.client.Client): The client that owns the current connection.
 
- client_info (google.api_core.client_info.ClientInfo): (Optional) instance used to generate user agent.
+ client_info (Optional[google.api_core.client_info.ClientInfo]): Instance used to generate user agent.
  """
 
  DEFAULT_API_ENDPOINT = "https://bigquery.googleapis.com"

google/cloud/bigquery/_pandas_helpers.py

@@ -472,10 +472,9 @@ def dataframe_to_parquet(dataframe, bq_schema, filepath, parquet_compression="SN
  columns in the DataFrame.
  filepath (str):
  Path to write Parquet file to.
- parquet_compression (str):
- (optional) The compression codec to use by the the
- ``pyarrow.parquet.write_table`` serializing method. Defaults to
- "SNAPPY".
+ parquet_compression (Optional[str]):
+ The compression codec to use by the the ``pyarrow.parquet.write_table``
+ serializing method. Defaults to "SNAPPY".
  https://arrow.apache.org/docs/python/generated/pyarrow.parquet.write_table.html#pyarrow-parquet-write-table
  """
  if pyarrow is None:

google/cloud/bigquery/client.py

@@ -295,9 +295,9 @@ def from_string(cls, dataset_id, default_project=None):
  A dataset ID in standard SQL format. If ``default_project``
  is not specified, this must include both the project ID and
  the dataset ID, separated by ``.``.
- default_project (str):
- Optional. The project ID to use when ``dataset_id`` does not
- include a project ID.
+ default_project (Optional[str]):
+ The project ID to use when ``dataset_id`` does not include a
+ project ID.
 
  Returns:
  DatasetReference: