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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 getSymbols(self):
 """Returns every symbol"""

        symbollist = []
        for rule in self.productions:
            for symbol in rule.leftside + rule.rightside:
                if symbol not in symbollist:
                    symbollist.append(symbol)
        symbollist += self.terminal_symbols
        return symbollist