Enforce string-formatting with f-strings (#10980)

* First third

* Styling and fix mistake

* Quality

* All the rest

* Treat %s and %d

* typo

* Missing )

* Apply suggestions from code review

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

src/transformers/testing_utils.py

@@ -62,7 +62,7 @@ def parse_flag_from_env(key, default=False):
             _value = strtobool(value)
         except ValueError:
             # More values are supported, but let's keep the message simple.
-            raise ValueError("If set, {} must be yes or no.".format(key))
+            raise ValueError(f"If set, {key} must be yes or no.")
     return _value
 
 
@@ -75,7 +75,7 @@ def parse_int_from_env(key, default=None):
         try:
             _value = int(value)
         except ValueError:
-            raise ValueError("If set, {} must be a int.".format(key))
+            raise ValueError(f"If set, {key} must be a int.")
     return _value