From 7ebf6e36a284942ccf747fd57f2e8043c067903c Mon Sep 17 00:00:00 2001
From: Lily Kuang <lily@preset.io>
Date: Tue, 26 May 2020 17:44:47 -0700
Subject: [PATCH] update doc string

---
 superset/sql_parse.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/superset/sql_parse.py b/superset/sql_parse.py
index 22d4c61df42a..4d2a8daf804c 100644
--- a/superset/sql_parse.py
+++ b/superset/sql_parse.py
@@ -216,7 +216,12 @@ def as_create_table(
 
     def _extract_from_token(self, token: Token):  # pylint: disable=too-many-branches
         """
-        Populate self._tables from token
+        <Identifier> store a list of subtokens and <IdentifierList> store lists of
+        subtoken list.
+
+        It extracts <IdentifierList> and <Identifier> from :param token: and loops through
+        all subtokens recursively. It finds table_name_preceding_token and passes
+        <IdentifierList> and <Identifier> to self._process_tokenlist to populate self._tables.
 
         :param token: instance of Token or child class, e.g. TokenList, to be processed
         """