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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 import_aliases(alias_source):
 """ Import aliases from a file or an URL. Args: alias_source: The source of the alias. It can be a filepath or an URL. """

    alias_table = get_alias_table()
    if is_url(alias_source):
        alias_source = retrieve_file_from_url(alias_source)
        alias_table.read(alias_source)
        os.remove(alias_source)
    else:
        alias_table.read(alias_source)
    _commit_change(alias_table)