docs: add docs signed_url expiration take default utc

google/cloud/storage/_signing.py

@@ -92,8 +92,8 @@ def get_expiration_seconds_v2(expiration):
 
     :type expiration: Union[Integer, datetime.datetime, datetime.timedelta]
     :param expiration: Point in time when the signed URL should expire. If
-                       expiration in datetime, then need to pass timezone
-                       with it. Default value of ``tzinfo`` is ``UTC``.
+                       a ``datetime`` instance is passed without an explicit
+                       ``tzinfo`` set,  it will be converted to ``UTC``.
 
     :raises: :exc:`TypeError` when expiration is not a valid type.
 
@@ -126,8 +126,8 @@ def get_expiration_seconds_v4(expiration):
 
     :type expiration: Union[Integer, datetime.datetime, datetime.timedelta]
     :param expiration: Point in time when the signed URL should expire. If
-                       expiration in datetime, then need to pass timezone
-                       with it. Default value of ``tzinfo`` is ``UTC``.
+                       a ``datetime`` instance is passed without an explicit
+                       ``tzinfo`` set,  it will be converted to ``UTC``.
 
     :raises: :exc:`TypeError` when expiration is not a valid type.
     :raises: :exc:`ValueError` when expiration is too large.
@@ -304,8 +304,8 @@ def generate_signed_url_v2(
 
     :type expiration: Union[Integer, datetime.datetime, datetime.timedelta]
     :param expiration: Point in time when the signed URL should expire. If
-                       expiration in datetime, then need to pass timezone with
-                       it. Default value of ``tzinfo`` is ``UTC``.
+                       a ``datetime`` instance is passed without an explicit
+                       ``tzinfo`` set,  it will be converted to ``UTC``.
 
     :type api_access_endpoint: str
     :param api_access_endpoint: (Optional) URI base. Defaults to empty string.
@@ -468,8 +468,8 @@ def generate_signed_url_v4(
 
     :type expiration: Union[Integer, datetime.datetime, datetime.timedelta]
     :param expiration: Point in time when the signed URL should expire. If
-                       expiration in datetime, then need to pass timezone with
-                       it. Default value of ``tzinfo`` is ``UTC``.
+                       a ``datetime`` instance is passed without an explicit
+                       ``tzinfo`` set,  it will be converted to ``UTC``.
 
     :type api_access_endpoint: str
     :param api_access_endpoint: (Optional) URI base. Defaults to

google/cloud/storage/blob.py

@@ -412,8 +412,8 @@ def generate_signed_url(
 
         :type expiration: Union[Integer, datetime.datetime, datetime.timedelta]
         :param expiration: Point in time when the signed URL should expire. If
-                           expiration in datetime, then need to pass timezone
-                           with it. Default value of ``tzinfo`` is ``UTC``.
+                           a ``datetime`` instance is passed without an explicit
+                           ``tzinfo`` set,  it will be converted to ``UTC``.
 
         :type api_access_endpoint: str
         :param api_access_endpoint: (Optional) URI base.

google/cloud/storage/bucket.py

@@ -2956,8 +2956,8 @@ def generate_signed_url(
 
         :type expiration: Union[Integer, datetime.datetime, datetime.timedelta]
         :param expiration: Point in time when the signed URL should expire. If
-                           expiration in datetime, then need to pass timezone
-                           with it. Default value of ``tzinfo`` is ``UTC``.
+                           a ``datetime`` instance is passed without an explicit
+                           ``tzinfo`` set,  it will be converted to ``UTC``.
 
         :type api_access_endpoint: str
         :param api_access_endpoint: (Optional) URI base.

google/cloud/storage/client.py

@@ -962,9 +962,9 @@ def generate_signed_post_policy_v4(
         :param blob_name: Object name.
 
         :type expiration: Union[Integer, datetime.datetime, datetime.timedelta]
-        :param expiration: Policy expiration time. If expiration in datetime,
-                           then need to pass timezone with it. Default value of
-                           ``tzinfo`` is ``UTC``.
+        :param expiration: Policy expiration time. If a ``datetime`` instance is
+                           passed without an explicit ``tzinfo`` set,  it will be
+                           converted to ``UTC``.
 
         :type conditions: list
         :param conditions: (Optional) List of POST policy conditions, which are