from __future__ import print_function
from datetime import datetime, timedelta, tzinfo

def fromutc(dt):
    "fromutc function copied from the Python docs"
    # raise ValueError error if dt.tzinfo is not self
    dtoff = dt.utcoffset()
    dtdst = dt.dst()
    # raise ValueError if dtoff is None or dtdst is None
    delta = dtoff - dtdst  # this is the timezones's standard offset
    if delta:
        dt += delta   # convert to standard local time
        dtdst = dt.dst()
        # raise ValueError if dtdst is None
    if dtdst:
        return dt + dtdst
    else:
        return dt

DSTDIFF = DSTOFFSET = timedelta(hours = 1)

class UKSummerTime(tzinfo):
    """Simple time zone which pretends to always be in summer time, since
        that's what shows the failure.
    """

    def utcoffset(self, dt):
        return DSTOFFSET

    def dst(self, dt):
        return DSTDIFF

    def tzname(self, dt):
        return 'UKSummerTime'


stz = UKSummerTime()
aware = datetime(2014, 4, 26, 12, 1, tzinfo=stz)
print(aware)

# This is the line which I believe is wrong -- it should now have converted
# the datetime value to the target timezone, but hasn't.
conv = stz.fromutc(aware)
print(conv)

ref_conv = fromutc(aware)
print(ref_conv)