Function parse_date_range 

pub fn parse_date_range(date_range: &str) -> Result<DateRange, &str>

parses string in (..()?)? format where date -> ‘today’ | yyyy-mm-dd | mm-dd returns the range (<earliest_tempus_date>, ), inclusive .. returns the range (, ), inclusive .. returns the range (, ), inclusive ‘today’ can be used in place of a date instead of typing today’s date a date without the year will search for this year