chore(internal): add a default_query method (#402)

Author: stainless-app[bot]

src/finch/_base_client.py

@@ -457,7 +457,7 @@ def _build_request(
                 raise RuntimeError(f"Unexpected JSON data type, {type(json_data)}, cannot merge with `extra_body`")
 
         headers = self._build_headers(options)
-        params = _merge_mappings(self._custom_query, options.params)
+        params = _merge_mappings(self.default_query, options.params)
         content_type = headers.get("Content-Type")
 
         # If the given Content-Type header is multipart/form-data then it
@@ -593,6 +593,12 @@ def default_headers(self) -> dict[str, str | Omit]:
             **self._custom_headers,
         }
 
+    @property
+    def default_query(self) -> dict[str, object]:
+        return {
+            **self._custom_query,
+        }
+
     def _validate_headers(
         self,
         headers: Headers,  # noqa: ARG002