feat: HasSize

Signed-off-by: Nathaniel Starkman <[email protected]>

Author: nstarman

src/array_api_typing/_array.py

@@ -111,6 +111,25 @@ def shape(self) -> tuple[int | None, ...]:
         ...
 
 
+class HasSize(Protocol):
+    """Protocol for array classes that have a size attribute."""
+
+    @property
+    def size(self) -> int | None:
+        """Number of elements in an array.
+
+        Returns:
+            int | None: number of elements in an array. The returned value must
+                be `None` if and only if one or more array dimensions are
+                unknown.
+
+        Notes:
+            This must equal the product of the array's dimensions.
+
+        """
+        ...
+
+
 # ============================================================================
 
 
@@ -563,6 +582,7 @@ class Array(
     HasMatrixTranspose,
     HasNDim,
     HasShape,
+    HasSize,
     # ------ Methods -------
     HasArrayNamespace[NS_co],
     CanArrayPos,