Fix usage part in README

README.md

@@ -83,6 +83,7 @@ First, from the command line install the `datasets` library
 
 then, from within python load the datasets library.
 
+    >>> import datasets
     >>> from datasets import load_dataset, Features, Value
 
 Specifiy column types to prevent pyarrow error.
@@ -90,7 +91,7 @@ Specifiy column types to prevent pyarrow error.
 features = Features({
     "Type": Value("string"),
     "DatasetName": Value("string"),
-    "AID": Value("int64"),
+    "AID": Value("string"), # Treat this as string to deal with NaN values
     "ID": Value("string"),
     "IDType": Value("string"),
     "SMILES": Value("string")