TypeError in address_masker when processing addresses with lok abbreviation

[wysockigrzegorz]

Bug description

This PR fixes a crash in the address_masker component of priv_masker, caused by incorrect usage of the Python list .append() method.

Problematic line:

masked_tokens = masked_tokens.append(doc[end])

This causes masked_tokens to become None, since list.append() returns None. As a result, any later use of masked_tokens (like if token in masked_tokens) crashes with:

TypeError: argument of type 'NoneType' is not iterable

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Reproduction

Minimal example (adapted from the official README):

ul. Juliusza Słowackiego 13 lok 3

This triggers a crash in search_address_nums_with_key_words().

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Fix

The incorrect line was replaced with:

masked_tokens.append(doc[end])

This keeps masked_tokens as a valid list and prevents the crash.

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Why this matters

This fix restores correct functionality to address matching involving apartment indicators like lok, lokal, etc., which are common in real-world Polish addresses.

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Pozdrowienia