Do not check file_path if it is None

src/client.py

@@ -450,14 +450,14 @@ def main():
                 path=input(f"Enter file to send:\t\t\t\t\t\t"),
                 action=action
             )
-            if not os.path.isfile(os.path.abspath(file_path)):
+            if file_path and not os.path.isfile(os.path.abspath(file_path)):
                 file_path = None
         elif action == 'receive':
             file_path = get_file_path(
                 path=input(f"Enter destination folder:\t\t\t\t\t\t"),
                 action=action
             )
-            if not os.path.isdir(os.path.abspath(file_path)):
+            if file_path and not os.path.isdir(os.path.abspath(file_path)):
                 file_path = None
     if password is None:
         logging.warning(