diff --git a/requirements.txt b/requirements.txt
index 6826e72d99a23a3f0105b0428f9417f69c9eb6e5..f79084ef28b5e98eaa614bcfe2e74eac5c6fdaa5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,6 +3,7 @@ coverage
 latexdatax
 numba
 numpy
+orderedset
 pandas
 pygraphviz
 pytest