add support for 'by <time>' (#839)

Author: noviluni

dateparser/data/date_translation_data/en.py

@@ -737,6 +737,7 @@
     },
     "skip": [
         "at",
+        "by",
         "on",
         "and",
         "ad",

dateparser_data/supplementary_language_data/date_translation_data/en.yaml

@@ -1,4 +1,4 @@
-skip: ["at", "on", "and", "ad", "m", "of", "st", "nd", "rd", "th", "about", "the", "just"]
+skip: ["at", "by", "on", "and", "ad", "m", "of", "st", "nd", "rd", "th", "about", "the", "just"]
 pertain: ["of"]
 
 sentence_splitter_group : 1

tests/test_freshness_date_parser.py

@@ -1491,6 +1491,7 @@ def test_inexplicit_dates(self, date_string, boundary, period):
         param('Today at 9 pm', date(2014, 9, 1), time(21, 0)),
         param('Today at 11:20 am', date(2014, 9, 1), time(11, 20)),
         param('Yesterday 1:20 pm', date(2014, 8, 31), time(13, 20)),
+        param('Yesterday by 13:20', date(2014, 8, 31), time(13, 20)),
         param('the day before yesterday 16:50', date(2014, 8, 30), time(16, 50)),
         param('2 Tage 18:50', date(2014, 8, 30), time(18, 50)),
         param('1 day ago at 2 PM', date(2014, 8, 31), time(14, 0)),