Remove f-strings without any expressions

pywidevine/pssh.py

@@ -122,7 +122,7 @@ class PSSH:
         if not isinstance(flags, int):
             raise TypeError(f"Expected flags to be an int not {flags!r}")
         if flags < 0:
-            raise ValueError(f"Invalid flags, cannot be less than 0.")
+            raise ValueError("Invalid flags, cannot be less than 0.")
 
         if version == 0 and key_ids is not None and init_data is not None:
             # v0 boxes use only init_data in the pssh field, but we can use the key_ids within the init_data

pywidevine/remotecdm.py

@@ -84,7 +84,7 @@ class RemoteCdm(Cdm):
             raise ValueError(f"This Remote CDM API does not seem to be a pywidevine serve API ({server}).")
         server_version = re.search(r"pywidevine serve v([\d.]+)", server, re.IGNORECASE)
         if not server_version:
-            raise ValueError(f"The pywidevine server API is not stating the version correctly, cannot continue.")
+            raise ValueError("The pywidevine server API is not stating the version correctly, cannot continue.")
         server_version = server_version.group(1)
         if server_version < "1.4.0":
             raise ValueError(f"This pywidevine serve API version ({server_version}) is not supported.")