fix mypy

Author: brokkoli71

src/zarr/api/asynchronous.py

@@ -554,7 +554,7 @@ async def array(
 
     # setup dtype
     kw_dtype = kwargs.get("dtype")
-    if kw_dtype is None:
+    if kw_dtype is None and hasattr(data, "dtype"):
         kwargs["dtype"] = data.dtype
     else:
         kwargs["dtype"] = kw_dtype

src/zarr/core/array.py

@@ -3850,7 +3850,7 @@ async def from_array(
         filters = data.filters
     if compressors is None:
         compressors = data.compressors
-    if serializer is None:
+    if serializer is "auto":
         serializer = data.serializer
     if fill_value is None:
         fill_value = data.fill_value