Note that child being the same as parent is considered valid in _isValidChildRes
@@ -146,7 +146,8 @@ H3Index H3_EXPORT(h3ToParent)(H3Index h, int parentRes) {
}
/**
- * Determines whether one resolution is a valid child resolution of another
+ * Determines whether one resolution is a valid child resolution of another.
+ * Each resolution is considered a valid child resolution of itself.
*
* @param parentRes int resolution of the parent
* @param childRes int resolution of the child
