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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 set_line_style(self, width = None, dash = None, dash_offset = 0):
 """change width and dash of a line"""

        if width is not None:
            self._add_instruction("set_line_width", width)

        if dash is not None:
            self._add_instruction("set_dash", dash, dash_offset)