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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 build_filter_stack(stack, options):
 """Setup and return a filter stack. Args: stack: :class:`~sqlparse.filters.FilterStack` instance options: Dictionary with options validated by validate_options. """

    # Token filter
    if options.get('keyword_case'):
        stack.preprocess.append(
            filters.KeywordCaseFilter(options['keyword_case']))

    if options.get('identifier_case'):
        stack.preprocess.append(
            filters.IdentifierCaseFilter(options['identifier_case']))

    if options.get('truncate_strings'):
        stack.preprocess.append(filters.TruncateStringFilter(
            width=options['truncate_strings'], char=options['truncate_char']))

    if options.get('use_space_around_operators', False):
        stack.enable_grouping()
        stack.stmtprocess.append(filters.SpacesAroundOperatorsFilter())

    # After grouping
    if options.get('strip_comments'):
        stack.enable_grouping()
        stack.stmtprocess.append(filters.StripCommentsFilter())

    if options.get('strip_whitespace') or options.get('reindent'):
        stack.enable_grouping()
        stack.stmtprocess.append(filters.StripWhitespaceFilter())

    if options.get('reindent'):
        stack.enable_grouping()
        stack.stmtprocess.append(
            filters.ReindentFilter(
                char=options['indent_char'],
                width=options['indent_width'],
                indent_after_first=options['indent_after_first'],
                indent_columns=options['indent_columns'],
                wrap_after=options['wrap_after'],
                comma_first=options['comma_first']))

    if options.get('reindent_aligned', False):
        stack.enable_grouping()
        stack.stmtprocess.append(
            filters.AlignedIndentFilter(char=options['indent_char']))

    if options.get('right_margin'):
        stack.enable_grouping()
        stack.stmtprocess.append(
            filters.RightMarginFilter(width=options['right_margin']))

    # Serializer
    if options.get('output_format'):
        frmt = options['output_format']
        if frmt.lower() == 'php':
            fltr = filters.OutputPHPFilter()
        elif frmt.lower() == 'python':
            fltr = filters.OutputPythonFilter()
        else:
            fltr = None
        if fltr is not None:
            stack.postprocess.append(fltr)

    return stack