关于python源码实现sqlite API 的问题

import datetime
import time
import collections.abc

from _sqlite3 import *

paramstyle = "qmark"

threadsafety = 1

apilevel = "2.0"

Date = datetime.date

Time = datetime.time

Timestamp = datetime.datetime

def DateFromTicks(ticks):
    return Date(*time.localtime(ticks)[:3])

def TimeFromTicks(ticks):
    return Time(*time.localtime(ticks)[3:6])

def TimestampFromTicks(ticks):
    return Timestamp(*time.localtime(ticks)[:6])

version_info = tuple([int(x) for x in version.split(".")])
sqlite_version_info = tuple([int(x) for x in sqlite_version.split(".")])

Binary = memoryview
collections.abc.Sequence.register(Row)

def register_adapters_and_converters():
    def adapt_date(val):
        return val.isoformat()

    def adapt_datetime(val):
        return val.isoformat(" ")

    def convert_date(val):
        return datetime.date(*map(int, val.split(b"-")))

    def convert_timestamp(val):
        datepart, timepart = val.split(b" ")
        year, month, day = map(int, datepart.split(b"-"))
        timepart_full = timepart.split(b".")
        hours, minutes, seconds = map(int, timepart_full[0].split(b":"))
        if len(timepart_full) == 2:
            microseconds = int('{:0<6.6}'.format(timepart_full[1].decode()))
        else:
            microseconds = 0

        val = datetime.datetime(year, month, day, hours, minutes, seconds, microseconds)
        return val


    register_adapter(datetime.date, adapt_date)
    register_adapter(datetime.datetime, adapt_datetime)
    register_converter("date", convert_date)
    register_converter("timestamp", convert_timestamp)

register_adapters_and_converters()

# Clean up namespace

del(register_adapters_and_converters)