fix up tutorial code blocks

docs/source/tutorial.rst

@@ -60,7 +60,7 @@ STAC objects. You can also pass ``satstac`` objects (e.g.
     import satstac
 
     col = satstac.Collection.open(f'{root_url}/catalog.json')
-    collection_cat = intake.open_stac_collection(url)
+    collection_cat = intake.open_stac_collection(col)
 
 Using the catalog
 -----------------
@@ -70,30 +70,57 @@ contents:
 
 .. ipython:: python
 
-    catalog = catalog['hurricane-harvey']['hurricane-harvey-0831']
-    for id, entry in catalog.items():
-        display(entry)
+    print(list(catalog))
+    cat = catalog['hurricane-harvey']
+
+    print(list(cat))
+    subcat = cat['hurricane-harvey-0831']
+
+    items = list(subcat)
+    print(items)
+
+
+
+When you locate an item of interest, you have access to metadata and methods to load assets into Python objects
+
+.. ipython:: python
+
+    item = subcat['Houston-East-20170831-103f-100d-0f4f-RGB']
+    print(type(item))
+    print(item.metadata)
+
+    assets = list(item)
+    print(assets)
+
+    asset = item['thumbnail']
+    print(type(asset))
+    print(asset.urlpath)
+
 
 If the catalog has too many entries to comfortably print all at once,
 you can narrow it by searching for a term (e.g. 'thumbnail'):
 
 .. ipython:: python
 
-    for id, entry in catalog.search('thumbnail').items():
-        display(entry)
+    for id, entry in subcat.search('thumbnail').items():
+        print(id)
+
+    asset = subcat['Houston-East-20170831-103f-100d-0f4f-RGB.thumbnail']
+    print(asset.urlpath)
+
 
 Loading a dataset
 -----------------
 
 Once you have identified a dataset, you can load it into a ``xarray.DataArray``
-using Intake's `to_dask()` method:
+using Intake's `to_dask()` method. This reads only metadata, and streams values over the network when required by computations or visualizations:
 
 .. ipython:: python
 
-    entry = catalog['thumbnail']
-    da = entry.to_dask()
+    da = asset.to_dask()
     display(da)
 
+
 Working with `sat-search`
 -------------------------
 
@@ -104,14 +131,15 @@ using `sat-search`:
 .. ipython:: python
 
     import satsearch
-
+    print(satsearch.__version__)
+    URL='https://earth-search.aws.element84.com/v0'
     results = satsearch.Search.search(
-        collection='landsat-8-l1',
-        bbox=[43.16, -11.32, 43.54, -11.96],
-        sort=['<datetime'], #earliest scene first
-        property=["landsat:tier=T1"])
+        url=URL,
+        collections=['landsat-8-l1-c1'],
+        bbox=[43.16, -11.32, 43.54, -11.96]
+    )
     items = results.items()
-    display(items)
+    items
 
 In the code section above, `items` is a `satstac.ItemsCollection` object.
 Intake-stac can turn this object into an Intake catalog: