--- a
+++ b/src/moscot/_constants.py
@@ -0,0 +1,13 @@
+# policies
+SEQUENTIAL = "sequential"
+STAR = "star"
+EXTERNAL_STAR = "external_star"
+TRIU = "triu"
+TRIL = "tril"
+EXPLICIT = "explicit"
+DUMMY = "dummy"
+# plotting
+CELL_TRANSITION = "cell_transition"
+SANKEY = "sankey"
+PUSH = "push"
+PULL = "pull"