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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 get_con_id(self):
 """ Return contribution id if available """

        con_id = ""
        if "contribution" in self.tables:
            if "id" in self.tables["contribution"].df.columns:
                con_id = str(self.tables["contribution"].df["id"].values[0])
        return con_id