将hex转换为bytes

def get_head_bytes(data_len,type_name):
    header_bytes =b''

    head_bytes =  struct.pack('<H',43605) //将两个short转换为bytes
    header_bytes+=head_bytes

    token = bytes.fromhex('10') //将hex转换为bytes
    header_bytes+=token

    wLen = struct.pack('<H',data_len)
    header_bytes+=wLen

    eStation =bytes.fromhex('01')
    header_bytes+=eStation

    ebedno =bytes.fromhex('01')
    header_bytes+=ebedno

    IFrameNo = struct.pack('<I',1)
    header_bytes +=IFrameNo

    eFilter = bytes.fromhex('01')
    header_bytes +=eFilter

    wGain = struct.pack('<H',400)
    header_bytes +=wGain

    if type_name=='I':
        eLead = bytes.fromhex('12')
    elif type_name=='II':
        eLead =bytes.fromhex('13')
    elif type_name=='V1':
        eLead = bytes.fromhex('14')
    elif type_name=='V5':
        eLead = bytes.fromhex('15')
    header_bytes +=eLead

    wSamp = struct.pack('<H',250)
    header_bytes +=wSamp

    tail1 = bytes.fromhex('FF')
    header_bytes +=tail1

    tail2 = bytes.fromhex('FF')
    header_bytes +=tail2
    return header_bytes