_rfc3339

# File lib/date/format.rb, line 1121
  def self._rfc3339(str) # :nodoc:
    if /\A\s*-?\d{4}-\d{2}-\d{2} # allow minus, anyway
        (t|\s)
        \d{2}:\d{2}:\d{2}(\.\d+)?
        (z|[-+]\d{2}:\d{2})\s*\z/x =~ str
      _parse(str)
    end
  end