diff --git a/ydb/iam/auth.py b/ydb/iam/auth.py
index 613b92ad..7b4fa4e8 100644
--- a/ydb/iam/auth.py
+++ b/ydb/iam/auth.py
@@ -99,22 +99,14 @@ def set_token_expiration_timeout(self, value):
     @classmethod
     def from_file(cls, key_file, iam_endpoint=None, iam_channel_credentials=None):
         with open(os.path.expanduser(key_file), "r") as r:
-            key = r.read()
-
-        return BaseJWTCredentials.from_content(
-            cls, key, iam_endpoint=iam_endpoint, iam_channel_credentials=iam_channel_credentials
-        )
-
-    @classmethod
-    def from_content(cls, key, iam_endpoint=None, iam_channel_credentials=None):
-        key_json = json.loads(key)
-        account_id = key_json.get("service_account_id", None)
+            output = json.loads(r.read())
+        account_id = output.get("service_account_id", None)
         if account_id is None:
-            account_id = key_json.get("user_account_id", None)
+            account_id = output.get("user_account_id", None)
         return cls(
             account_id,
-            key_json["id"],
-            key_json["private_key"],
+            output["id"],
+            output["private_key"],
             iam_endpoint=iam_endpoint,
             iam_channel_credentials=iam_channel_credentials,
         )