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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 main():
 """Script to upgrade a Cisco ASA."""

    try:
        ip_addr = raw_input("Enter ASA IP address: ")
    except NameError:
        ip_addr = input("Enter ASA IP address: ")
    my_pass = getpass()
    start_time = datetime.now()
    print(">>>> {}".format(start_time))

    net_device = {
        "device_type": "cisco_asa",
        "ip": ip_addr,
        "username": "admin",
        "password": my_pass,
        "secret": my_pass,
        "port": 22,
    }

    print("\nLogging in to ASA")
    ssh_conn = ConnectHandler(**net_device)
    print()

    # ADJUST TO TRANSFER IMAGE FILE
    dest_file_system = "disk0:"
    source_file = "test1.txt"
    dest_file = "test1.txt"
    alt_dest_file = "asa825-59-k8.bin"

    with FileTransfer(
        ssh_conn,
        source_file=source_file,
        dest_file=dest_file,
        file_system=dest_file_system,
    ) as scp_transfer:

        if not scp_transfer.check_file_exists():
            if not scp_transfer.verify_space_available():
                raise ValueError("Insufficient space available on remote device")

            print("Enabling SCP")
            output = asa_scp_handler(ssh_conn, mode="enable")
            print(output)

            print("\nTransferring file\n")
            scp_transfer.transfer_file()

            print("Disabling SCP")
            output = asa_scp_handler(ssh_conn, mode="disable")
            print(output)

        print("\nVerifying file")
        if scp_transfer.verify_file():
            print("Source and destination MD5 matches")
        else:
            raise ValueError("MD5 failure between source and destination files")

    print("\nSending boot commands")
    full_file_name = "{}/{}".format(dest_file_system, alt_dest_file)
    boot_cmd = "boot system {}".format(full_file_name)
    output = ssh_conn.send_config_set([boot_cmd])
    print(output)

    print("\nVerifying state")
    output = ssh_conn.send_command("show boot")
    print(output)

    # UNCOMMENT TO PERFORM WR MEM AND RELOAD
    # print("\nWrite mem and reload")
    # output = ssh_conn.send_command_expect('write mem')
    # output += ssh_conn.send_command('reload')
    # output += ssh_conn.send_command('y')
    # print(output)

    print("\n>>>> {}".format(datetime.now() - start_time))
    print()