Class method which returns a list of WHERE clause fragments to search for services with tower/sector given by HASHREF. Can contain 'towernum' and 'sectornum' keys, either of which can be an arrayref or a single value. To use this, the search needs to join to tower_sector.
towernum or sectornum can also contain 'none' to allow null values.
Hey! The above document had some coding errors, which are explained below:
'=item' outside of any '=over'
=over without closing =back