Return a list of the substrings in the string, using sep as the separator string.
sep
The separator used to split the string.
When set to None (the default value), will split on any
whitespace character (including \n \r \t \f and spaces) and
will discard empty strings from the result.
maxsplit
Maximum number of splits.
-1 (the default value) means no limit.
Splitting starts at the end of the string and works to the front.