Add the op.

src/storage.rs

@@ -1,3 +1,5 @@
+use crate::{DType, Device};
+
 #[allow(dead_code)]
 pub(crate) enum Storage {
     Cpu {
@@ -5,3 +7,17 @@ pub(crate) enum Storage {
         buffer: Vec<u8>,
     },
 }
+
+impl Storage {
+    pub(crate) fn device(&self) -> Device {
+        match self {
+            Self::Cpu { .. } => Device::Cpu,
+        }
+    }
+
+    pub(crate) fn dtype(&self) -> DType {
+        match self {
+            Self::Cpu { dtype, .. } => *dtype,
+        }
+    }
+}