def updateRank(rank1, rank2, movieTitle):

    # Create a new connection
    con = connection()

    # Create a cursor on the connection
    cursor = con.cursor()

    try:
        float(rank1)
    except ValueError:
        return [("status",),("error",),]
    try:
        float(rank2)
    except ValueError:
        return [("status",),("error",),]

    # See if rank1, rank2 are out of range [0:10]
    if float(rank1) < 0 or float(rank1) > 10:
        return [("status",),("error",),]
    if float(rank2) < 0 or float(rank2) > 10:
        return [("status",),("error",),]


    # See if movie exists in the database
    sql_exists = """ select *
                    from movie
                    where exists
                        (select title from movie where title = %s) """
    cursor.execute(sql_exists, str(movieTitle))
    result = cursor.fetchall()
    if result == ():
        return [("status",),("error",),]


    # See if multiple movies with the same title exist in the database
    sql_multiple = """ select count(distinct m.title)
                       from movie m
                       where m.title = %s """
    cursor.execute(sql_multiple, str(movieTitle))
    result = cursor.fetchall()
    if result > ((1,),):
        return [("status",),("error",),]


    # Obtain movie's rank
    sql_test_null = "select rank from movie where title = %s"
    cursor.execute(sql_test_null, str(movieTitle))
    result = cursor.fetchall()
    # See if movie's rank is NULL
    if result == ((None,),):
         try:
             sql_query = """ update movie
                             set rank = (%s + %s) / 2
                             where title = %s """
             # Execute the sql command
             cursor.execute(sql_query, (str(rank1), str(rank2), str(movieTitle)))
             # Commit changes in the database
             con.commit()
         except:
             # Rollback in case there is an error
             con.rollback()
    # If movie's rank is NOT NULL
    else:
        try:
            sql_query = """ update movie
                            set rank = (%s + %s + rank) / 3
                            where title = %s """
            # Execute the sql command
            cursor.execute(sql_query, (str(rank1), str(rank2), str(movieTitle)))
            # Commit changes in the database
            con.commit()
        except:
            # Rollback in case there is an error
            con.rollback()

    print (rank1, rank2, movieTitle)

    return [("status",),("ok",),]

    con.close()