'Retrieve BlobInfo by key or list of keys.
Args:
blob_keys: A key or a list of keys.  Keys may be instances of str,
unicode and BlobKey.
Returns:
A BlobInfo instance associated with provided key or a list of BlobInfo
instances if a list of keys was provided.  Keys that are not found in
Blobstore return None as their values.'

@classmethod
def get(cls, blob_keys):

    blob_keys = cls.__normalize_and_convert_keys(blob_keys)
    try:
        entities = datastore.Get(blob_keys)
    except datastore_errors.EntityNotFoundError:
        return None
    if isinstance(entities, datastore.Entity):
        return BlobInfo(entities)
    else:
        references = []
        for entity in entities:
            if (entity is not None):
                references.append(BlobInfo(entity))
            else:
                references.append(None)
        return references
