diff --git a/fsspec/core.py b/fsspec/core.py
index de66be28d..e79f2a894 100644
--- a/fsspec/core.py
+++ b/fsspec/core.py
@@ -578,7 +578,7 @@ def expand_paths_if_needed(paths, mode, num, fs, name_function):
     paths = list(paths)
 
     if "w" in mode:  # read mode
-        if sum([1 for p in paths if "*" in p]) > 1:
+        if sum(1 for p in paths if "*" in p) > 1:
             raise ValueError(
                 "When writing data, only one filename mask can be specified."
             )