diff --git a/R/mfairUtils.R b/R/mfairUtils.R
new file mode 100644
index 0000000..e423817
--- /dev/null
+++ b/R/mfairUtils.R
@@ -0,0 +1 @@
+setClassUnion(name = "matrixORdgCMatrix", members = c("matrix", "dgCMatrix"))