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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 update_ledger(self, ledger_id, description=None):
 """Update ledger info Arguments: ledger_id: Ledger id assigned by mCASH description: Description of the Ledger and it's usage """

        arguments = {'description': description}
        return self.do_req('PUT',
                           self.merchant_api_base_url + '/ledger/' +
                           ledger_id + '/', arguments)