fix incorrect README, remove empty lines

tools/IS_STAG/README.md

@@ -1,9 +1,9 @@
 # check_url.py
 
 This script compares the new and current URLs based on the bitstream name.
-use your username (--user) and password (--password) to dspace-ZCU. Use your path (--input_dir) (default: data) and file (--JSON_name).
+Use your username (--user) and password (--password) to dspace-ZCU. Use your path (--input_dir) (default: data) and file (--JSON_name).
 Use you keys: new_key (--new_key) and cur_key (--cur_key) (default: new_url and cur_url).
 
 ```
-python policy.py --endpoint="https://naos-be.zcu.cz/server/api" ----user="[user] "--password=[password] --JSON_name="input.json"
+python check_url.py --endpoint="https://naos-be.zcu.cz/server/api" ----user="[user] "--password=[password] --JSON_name="input.json"
 ```

tools/IS_STAG/check_url.py

@@ -60,7 +60,7 @@ def extract_name(self, url: str) -> str:
         logging.error(f"Url {url} doesn't contains pattern {pattern}!")
         return None
 
-    def get_bitstream_name(self, uuid):
+    def get_bitstream_name(self, uuid: str) -> str:
         """
         Fetch the bitstream name from the DSpace backend using the UUID.
         """