'Build a search engine from the aggregated keywords.
Builds a case insensitive search engine when passing
``ignore_case=True``, and a case sensitive engine otherwise.'

def build(self, ignore_case=False, acora=None):

    if (acora is None):
        if self.for_unicode:
            acora = UnicodeAcora
        else:
            acora = BytesAcora
    if ((self.for_unicode == False) and ignore_case):
        import sys
        if (sys.version_info[0] >= 3):
            raise ValueError('Case    insensitive    search    is    not    supported    for    byte    strings    in    Python    3')
    return acora(*nfa2dfa(self.tree, ignore_case))
