def oa_address_to_address(oa_address)
      decode_address = decode_base58(oa_address)
      btc_addr = decode_address[2..-9]
      btc_checksum = checksum(btc_addr)
      encode_base58(btc_addr + btc_checksum)
    end
def oa_address_to_address(oa_address)
      decode_address = decode_base58(oa_address)
      btc_addr = decode_address[2..-9]
      btc_checksum = checksum(btc_addr)
      encode_base58(btc_addr + btc_checksum)
    end
convert open assets address to bitcoin address
 @param [String] oa_address The Open Assets Address.
 @return [String] The Bitcoin address.