Return an iterator on keys.
If the optional prefix
string is provided, only yield keys starting
with this prefix.
If the optional wildcard
is provided as a single character string,
then the prefix is treated as a simple pattern using this character
as a wildcard.
The optional how
argument is used to control how strings are matched
using one of these possible values:
- ahocorasick.MATCH_EXACT_LENGTH (default) Yield matches that have the same exact length as the prefix length.
- ahocorasick.MATCH_AT_LEAST_PREFIX Yield matches that have a length greater or equal to the prefix length.
- ahocorasick.MATCH_AT_MOST_PREFIX Yield matches that have a length lesser or equal to the prefix length.