Accepts the following hash arguments (either a string or a symbol):
- pattern
- A pattern format string.
- date_pattern
- A Time#strftime format string. See the Ruby Time class for details.
- date_method
- As an option to date_pattern, specify which Time.now method to call. For
example, usec or to_s. Specify it as a String or Symbol.
The default date format is ISO8601, which looks like this:
yyyy-mm-dd hh:mm:ss => 2001-01-12 13:15:50