diff --git a/anymail/backends/unisender_go.py b/anymail/backends/unisender_go.py
index a1e187d6..124cbef0 100644
--- a/anymail/backends/unisender_go.py
+++ b/anymail/backends/unisender_go.py
@@ -136,9 +136,7 @@ def __init__(
         http_headers["Accept"] = "application/json"
         http_headers["X-API-KEY"] = backend.api_key
         kwargs["headers"] = http_headers
-        super().__init__(
-            message, defaults, backend, *args, **kwargs
-        )
+        super().__init__(message, defaults, backend, *args, **kwargs)
 
     def get_api_endpoint(self) -> str:
         return "email/send.json"
@@ -298,7 +296,9 @@ def set_send_at(self, send_at: datetime | str) -> None:
             # "Date and time in the format “YYYY-MM-DD hh:mm:ss” in the UTC time zone."
             # If send_at is a datetime, it's guaranteed to be aware, but maybe not UTC.
             # Convert to UTC, then strip tzinfo to avoid isoformat "+00:00" at end.
-            send_at_utc = send_at.astimezone(timezone.utc).replace(tzinfo=None)  # type:ignore[union-attr]
+            send_at_utc = send_at.astimezone(  # type:ignore[union-attr]
+                timezone.utc
+            ).replace(tzinfo=None)
             send_at_formatted = send_at_utc.isoformat(sep=" ", timespec="seconds")
             assert len(send_at_formatted) == 19
         except (AttributeError, TypeError):