start,end
is a character vector of ICD-9 codes. If fewer than five characters is given
in a code, then the digits are greedily assigned to hundreds, then tens,
then units, before the decimal parts. E.g. "10" becomes "010", not "0010"
inferParents
single logical value, if TRUE, will infer and include a
parent code if a range ends with a value which terminates a higher-level
code. E.g. "043"the codes from 0440 to 04499, are covered, but "044" is not explicit. If
inferParents
is TRUE, "0