docs: def listunspent(
          self,
          address: str="",
          minconf: int=1,
          maxconf: int=999999,
      ) -> list:
          '''list UTXOs
          modified version to allow filtering by address.
          '''
          if address:
              return self.req("listunspent", [minconf, maxconf, [address]])
  
          return self.req("listunspent", [minconf, maxconf])