Collect book names from RASB Bible, Leningrad Codex, or Septuagint based on the dates outlined in 'author_data' dataset.
by_date(date_range, testament)
a character vector of standardized book names to be passed to other functions
a character vector or length 1, written as a date range, "1445 - 1405 BC", specifying the probable writing period of the Old or New Testament books
a character vector of length 1 specifying the testament corresponding to the provided date range