What is the average Channel 4 weekly rank for less than 2.19 million viewers on December 7, 2007?
CREATE TABLE table_70274 (
    "Episode #" real,
    "Title" text,
    "Airdate" text,
    "Viewers (millions)" real,
    "Channel 4 weekly rank a" real
)
SELECT AVG("Channel 4 weekly rank a") FROM table_70274 WHERE "Viewers (millions)" < '2.19' AND "Airdate" = 'december 7, 2007'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the average Channel 4 weekly rank for less than 2.19 million viewers on December 7, 2007? ### Input: CREATE TABLE table_70274 (
    "Episode #" real,
    "Title" text,
    "Airdate" text,
    "Viewers (millions)" real,
    "Channel 4 weekly rank a" real
) ### Response: SELECT AVG("Channel 4 weekly rank a") FROM table_70274 WHERE "Viewers (millions)" < '2.19' AND "Airdate" = 'december 7, 2007'