diff --git a/docs/pyerrors/input/hadrons.html b/docs/pyerrors/input/hadrons.html
index e9df8e62..3668a473 100644
--- a/docs/pyerrors/input/hadrons.html
+++ b/docs/pyerrors/input/hadrons.html
@@ -390,6 +390,18 @@
return result_dict
+def _epsilon_tensor(i, j, k, o):
+ """Rank-4 epsilon tensor
+
+ Extension of https://codegolf.stackexchange.com/a/160375
+ """
+ test_set = set((i, j, k, o))
+ if not (test_set <= set((1, 2, 3, 4)) or test_set <= set((0, 1, 2, 3))):
+ raise Exception("Unexpected input", i, j, k, o)
+
+ return (i - j) * (j - k) * (k - i) * (i - o) * (j - o) * (o - k) / 12
+
+
def _get_lorentz_names(name):
assert len(name) == 2