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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def __parse_aliases_stream(self, stream):
 """Parse aliases stream. The stream contains a list of usernames (they can be email addresses their username aliases. Each line has a username and an alias separated by tabs. Comment lines start with the hash character (#). Example: # List of email aliases jsmith@example.com jsmith@example.net jsmith@example.net johnsmith@example.com jdoe@example.com john_doe@example.com jdoe@example john_doe@example.com """

        if not stream:
            return

        f = self.__parse_aliases_line

        for alias_entries in self.__parse_stream(stream, f):
            alias = alias_entries[0]
            username = alias_entries[1]

            self.__raw_aliases[alias] = username