ref: a049f8fcefab3384d0b07ef8603c21dd0ee85995
dir: /sys/src/cmd/python/Doc/lib/sqlite3/adapter_point_1.py/
import sqlite3
class Point(object):
    def __init__(self, x, y):
        self.x, self.y = x, y
    def __conform__(self, protocol):
        if protocol is sqlite3.PrepareProtocol:
            return "%f;%f" % (self.x, self.y)
con = sqlite3.connect(":memory:")
cur = con.cursor()
p = Point(4.0, -3.2)
cur.execute("select ?", (p,))
print cur.fetchone()[0]