docs: def parse_date(self, value):
          """A lazy method to parse anything to date.
  
          If input data type is:
  
          - string: parse date from it
          - integer: use from ordinal
          - datetime: use date part
          - date: just return it
          """
          if value is None:
              raise Exception("Unable to parse date from %r" % value)
          elif isinstance(value, string_types):
              return self.str2date(value)
          elif isinstance(value, int):
              return date.fromordinal(value)
          elif isinstance(value, datetime):
              return value.date()
          elif isinstance(value, date):
              return value
          else:
              raise Exception("Unable to parse date from %r" % value)