def __init__(self, db, roots):
     BaseFinder.__init__(self, db, roots)
 def __init__(self, db, roots, sig_type, verbose_progress=1):
     BaseFinder.__init__(self, db, roots)
     self.verbose_progress = verbose_progress
     assert sig_type in [1, 2, 3, 4, 5]
     self.iht = sig_type