diff --git a/pandas/_libs/index.pyx b/pandas/_libs/index.pyx
index 4d26842cc0277..4a9b504ffb0d9 100644
--- a/pandas/_libs/index.pyx
+++ b/pandas/_libs/index.pyx
@@ -479,7 +479,6 @@ cdef class PeriodEngine(Int64Engine):
             return scalar.value
         if isinstance(scalar, Period):
             # NB: we assume that we have the correct freq here.
-            # TODO: potential optimize by checking for _Period?
             return scalar.ordinal
         raise TypeError(scalar)