Docs: import datetime as dt in examples

Doc/includes/tzinfo_examples.py

@@ -1,68 +1,70 @@
-from datetime import tzinfo, timedelta, datetime
-
-ZERO = timedelta(0)
-HOUR = timedelta(hours=1)
-SECOND = timedelta(seconds=1)
+import datetime as dt
 
 # A class capturing the platform's idea of local time.
 # (May result in wrong values on historical times in
 #  timezones where UTC offset and/or the DST rules had
 #  changed in the past.)
 import time as _time
 
-STDOFFSET = timedelta(seconds = -_time.timezone)
+ZERO = dt.timedelta(0)
+HOUR = dt.timedelta(hours=1)
+SECOND = dt.timedelta(seconds=1)
+
+STDOFFSET = dt.timedelta(seconds=-_time.timezone)
 if _time.daylight:
-    DSTOFFSET = timedelta(seconds = -_time.altzone)
+    DSTOFFSET = dt.timedelta(seconds=-_time.altzone)
 else:
     DSTOFFSET = STDOFFSET
 
 DSTDIFF = DSTOFFSET - STDOFFSET
 
-class LocalTimezone(tzinfo):
 
-    def fromutc(self, dt):
+class LocalTimezone(dt.tzinfo):
+
+    def fromutc(self, when):
         assert dt.tzinfo is self
-        stamp = (dt - datetime(1970, 1, 1, tzinfo=self)) // SECOND
+        stamp = (when - dt.datetime(1970, 1, 1, tzinfo=self)) // SECOND
         args = _time.localtime(stamp)[:6]
         dst_diff = DSTDIFF // SECOND
         # Detect fold
         fold = (args == _time.localtime(stamp - dst_diff))
-        return datetime(*args, microsecond=dt.microsecond,
-                        tzinfo=self, fold=fold)
+        return dt.datetime(*args, microsecond=when.microsecond,
+                           tzinfo=self, fold=fold)
 
-    def utcoffset(self, dt):
-        if self._isdst(dt):
+    def utcoffset(self, when):
+        if self._isdst(when):
             return DSTOFFSET
         else:
             return STDOFFSET
 
-    def dst(self, dt):
-        if self._isdst(dt):
+    def dst(self, when):
+        if self._isdst(when):
             return DSTDIFF
         else:
             return ZERO
 
-    def tzname(self, dt):
-        return _time.tzname[self._isdst(dt)]
+    def tzname(self, when):
+        return _time.tzname[self._isdst(when)]
 
-    def _isdst(self, dt):
-        tt = (dt.year, dt.month, dt.day,
-              dt.hour, dt.minute, dt.second,
-              dt.weekday(), 0, 0)
+    def _isdst(self, when):
+        tt = (when.year, when.month, when.day,
+              when.hour, when.minute, when.second,
+              when.weekday(), 0, 0)
         stamp = _time.mktime(tt)
         tt = _time.localtime(stamp)
         return tt.tm_isdst > 0
 
+
 Local = LocalTimezone()
 
 
 # A complete implementation of current DST rules for major US time zones.
 
-def first_sunday_on_or_after(dt):
-    days_to_go = 6 - dt.weekday()
+def first_sunday_on_or_after(when):
+    days_to_go = 6 - when.weekday()
     if days_to_go:
-        dt += timedelta(days_to_go)
-    return dt
+        when += dt.timedelta(days_to_go)
+    return when
 
 
 # US DST Rules
@@ -75,21 +77,22 @@ def first_sunday_on_or_after(dt):
 #
 # In the US, since 2007, DST starts at 2am (standard time) on the second
 # Sunday in March, which is the first Sunday on or after Mar 8.
-DSTSTART_2007 = datetime(1, 3, 8, 2)
+DSTSTART_2007 = dt.datetime(1, 3, 8, 2)
 # and ends at 2am (DST time) on the first Sunday of Nov.
-DSTEND_2007 = datetime(1, 11, 1, 2)
+DSTEND_2007 = dt.datetime(1, 11, 1, 2)
 # From 1987 to 2006, DST used to start at 2am (standard time) on the first
 # Sunday in April and to end at 2am (DST time) on the last
 # Sunday of October, which is the first Sunday on or after Oct 25.
-DSTSTART_1987_2006 = datetime(1, 4, 1, 2)
-DSTEND_1987_2006 = datetime(1, 10, 25, 2)
+DSTSTART_1987_2006 = dt.datetime(1, 4, 1, 2)
+DSTEND_1987_2006 = dt.datetime(1, 10, 25, 2)
 # From 1967 to 1986, DST used to start at 2am (standard time) on the last
 # Sunday in April (the one on or after April 24) and to end at 2am (DST time)
 # on the last Sunday of October, which is the first Sunday
 # on or after Oct 25.
-DSTSTART_1967_1986 = datetime(1, 4, 24, 2)
+DSTSTART_1967_1986 = dt.datetime(1, 4, 24, 2)
 DSTEND_1967_1986 = DSTEND_1987_2006
 
+
 def us_dst_range(year):
     # Find start and end times for US DST. For years before 1967, return
     # start = end for no DST.
@@ -100,63 +103,63 @@ def us_dst_range(year):
     elif 1966 < year < 1987:
         dststart, dstend = DSTSTART_1967_1986, DSTEND_1967_1986
     else:
-        return (datetime(year, 1, 1), ) * 2
+        return (dt.datetime(year, 1, 1), ) * 2
 
     start = first_sunday_on_or_after(dststart.replace(year=year))
     end = first_sunday_on_or_after(dstend.replace(year=year))
     return start, end
 
 
-class USTimeZone(tzinfo):
+class USTimeZone(dt.tzinfo):
 
     def __init__(self, hours, reprname, stdname, dstname):
-        self.stdoffset = timedelta(hours=hours)
+        self.stdoffset = dt.timedelta(hours=hours)
         self.reprname = reprname
         self.stdname = stdname
         self.dstname = dstname
 
     def __repr__(self):
         return self.reprname
 
-    def tzname(self, dt):
-        if self.dst(dt):
+    def tzname(self, when):
+        if self.dst(when):
             return self.dstname
         else:
             return self.stdname
 
-    def utcoffset(self, dt):
-        return self.stdoffset + self.dst(dt)
+    def utcoffset(self, when):
+        return self.stdoffset + self.dst(when)
 
-    def dst(self, dt):
-        if dt is None or dt.tzinfo is None:
+    def dst(self, when):
+        if when is None or when.tzinfo is None:
             # An exception may be sensible here, in one or both cases.
             # It depends on how you want to treat them.  The default
             # fromutc() implementation (called by the default astimezone()
-            # implementation) passes a datetime with dt.tzinfo is self.
+            # implementation) passes a datetime with when.tzinfo is self.
             return ZERO
-        assert dt.tzinfo is self
-        start, end = us_dst_range(dt.year)
+        assert when.tzinfo is self
+        start, end = us_dst_range(when.year)
         # Can't compare naive to aware objects, so strip the timezone from
-        # dt first.
-        dt = dt.replace(tzinfo=None)
+        # when first.
+        when = when.replace(tzinfo=None)
         if start + HOUR <= dt < end - HOUR:
             # DST is in effect.
             return HOUR
-        if end - HOUR <= dt < end:
-            # Fold (an ambiguous hour): use dt.fold to disambiguate.
-            return ZERO if dt.fold else HOUR
-        if start <= dt < start + HOUR:
+        if end - HOUR <= when < end:
+            # Fold (an ambiguous hour): use when.fold to disambiguate.
+            return ZERO if when.fold else HOUR
+        if start <= when < start + HOUR:
             # Gap (a non-existent hour): reverse the fold rule.
-            return HOUR if dt.fold else ZERO
+            return HOUR if when.fold else ZERO
         # DST is off.
         return ZERO
 
-    def fromutc(self, dt):
-        assert dt.tzinfo is self
-        start, end = us_dst_range(dt.year)
+    def fromutc(self, when):
+        assert when.tzinfo is self
+        start, end = us_dst_range(when.year)
         start = start.replace(tzinfo=self)
         end = end.replace(tzinfo=self)
-        std_time = dt + self.stdoffset
+        std_time = when + self.stdoffset
         dst_time = std_time + HOUR
         if end <= dst_time < end + HOUR:
             # Repeated hour