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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 simple_polygon_without_brush(layer, width='0.26', color=QColor('black')):
 """Simple style to apply a border line only to a polygon layer. :param layer: The layer to style. :type layer: QgsVectorLayer :param color: Color to use for the line. Default to black. :type color: QColor :param width: Width to use for the line. Default to '0.26'. :type width: str """

    registry = QgsApplication.symbolLayerRegistry()
    line_metadata = registry.symbolLayerMetadata("SimpleLine")
    symbol = QgsSymbol.defaultSymbol(layer.geometryType())

    # Line layer
    line_layer = line_metadata.createSymbolLayer(
        {
            'width': width,
            'color': color.name(),
            'offset': '0',
            'penstyle': 'solid',
            'use_custom_dash': '0',
            'joinstyle': 'bevel',
            'capstyle': 'square'
        })

    # Replace the default layer with our custom line
    symbol.deleteSymbolLayer(0)
    symbol.appendSymbolLayer(line_layer)

    renderer = QgsSingleSymbolRenderer(symbol)
    layer.setRenderer(renderer)