Address PR feedback

onnxscript/rewriter/pattern.py

@@ -282,7 +282,7 @@ def _to_value_pattern(
         return x
     if isinstance(x, (int, float)):
         return Constant(x)
-    if isinstance(x, list):
+    if isinstance(x, Sequence):
         if all(isinstance(i, (int, float)) for i in x):
             return Constant(x)
         raise ValueError("Only lists of int/float can be used as a ValuePattern")
@@ -602,12 +602,12 @@ class Constant(ValuePattern):
 
     def __init__(
         self,
-        value: int | float | list[int] | list[float],
+        value: int | float | Sequence[int] | Sequence[float],
         rel_tol: float = 1e-5,
         abs_tol: float = 1e-8,
     ) -> None:
         super().__init__(None)
-        self._value = value
+        self._value = list(value) if isinstance(value, Sequence) else value
         self._rel_tol = rel_tol
         self._abs_tol = abs_tol
 
@@ -685,6 +685,11 @@ def visit(value_patterns: Sequence[ValuePattern | None]) -> None:
 
 
 def _add_backward_slice(node: NodePattern, backward_slice: set[NodePattern]) -> None:
+    """Adds all nodes in the backward slice of given node to the set `backward_slice`.
+
+    The backward slice of a node is the set of all nodes that are reachable from the node
+    in a backward traversal from the given node.
+    """
     if node in backward_slice:
         return
     backward_slice.add(node)