def __init__(<EOL>self, parts_by_doc=None, n_max=<NUM_LIT:3>, expand=True, split_tokens=["<STR_LIT:->", "<STR_LIT:/>"]<EOL>):
super(MentionNgrams, self).__init__(n_max=n_max, split_tokens=split_tokens)<EOL>self.parts_by_doc = parts_by_doc<EOL>self.expander = expand_part_range if expand else (lambda x: [x])<EOL>
MentionNgrams specifically for transistor parts.

        :param parts_by_doc: a dictionary d where d[document_name.upper()] =
            [partA, partB, ...]