warning: negative steps are not supported in String.slice/2, pass 1..-1//1 instead
  (elixir 1.19.3) lib/string.ex:2486: String.slice/2
  (microformats2 1.0.1) lib/helpers/date_time_normalizer.ex:80: Microformats2.Helpers.DateTimeNormalizer.normalized_time_zone_offset/1
  (microformats2 1.0.1) lib/items/dt_prop.ex:133: Microformats2.Items.DtProp.parse_date_values/2
  (microformats2 1.0.1) lib/items/dt_prop.ex:25: Microformats2.Items.DtProp.parsed_prop/2
  (microformats2 1.0.1) lib/items.ex:122: anonymous fn/7 in Microformats2.Items.gen_prop/8
  (elixir 1.19.3) lib/enum.ex:2520: Enum."-reduce/3-lists^foldl/2-0-"/3

warning: negative steps are not supported in String.slice/2, pass 1..-1//1 instead
  (elixir 1.19.3) lib/string.ex:2486: String.slice/2
  (microformats2 1.0.1) lib/helpers/date_time_normalizer.ex:80: Microformats2.Helpers.DateTimeNormalizer.normalized_time_zone_offset/1
  (microformats2 1.0.1) lib/items/dt_prop.ex:133: Microformats2.Items.DtProp.parse_date_values/2
  (microformats2 1.0.1) lib/items/dt_prop.ex:25: Microformats2.Items.DtProp.parsed_prop/2
  (microformats2 1.0.1) lib/items.ex:122: anonymous fn/7 in Microformats2.Items.gen_prop/8
  (elixir 1.19.3) lib/enum.ex:2520: Enum."-reduce/3-lists^foldl/2-0-"/3

warning: negative steps are not supported in String.slice/2, pass 1..-1//1 instead
  (elixir 1.19.3) lib/string.ex:2486: String.slice/2
  (microformats2 1.0.1) lib/helpers/date_time_normalizer.ex:80: Microformats2.Helpers.DateTimeNormalizer.normalized_time_zone_offset/1
  (microformats2 1.0.1) lib/items/dt_prop.ex:59: Microformats2.Items.DtProp.parsed_prop/2
  (microformats2 1.0.1) lib/items.ex:122: anonymous fn/7 in Microformats2.Items.gen_prop/8
  (elixir 1.19.3) lib/enum.ex:2520: Enum."-reduce/3-lists^foldl/2-0-"/3
  (microformats2 1.0.1) lib/items.ex:116: Microformats2.Items.gen_prop/8