Error using

I am working on and and I am trying to embed a
fixed sequence in the payload part of my packet. However, when i try to
receive the data using rx_voice, i get an error saying

terminate called after throwing an instance of ‘std::runtime_error’
what(): msg length is not a multiple of d_itemsize
Aborted (core dumped)

I have added only one line in make_packet in and it
looks like this:(just the important lines as i thought)

def make_packet(payload, samples_per_symbol, bits_per_symbol,
access_code=default_access_code, pad_for_usrp=True):

(packed_access_code, padded) = 

(packed_preamble, ignore) =
payload = packed_preamble + payload
payload_with_crc = gru.gen_and_append_crc32(payload)
pkt = ‘’.join((packed_access_code, make_header(L),
whiten(payload_with_crc), ‘\x55’))

if pad_for_usrp:
    pkt = pkt + (_npadding_bytes(len(pkt), samples_per_symbol, 

bits_per_symbol) * ‘\x55’)

return pkt

Can anyone please explain how to remove this error. I want to add fixed
sequence so that it helps in calculation of BER.

Pratik Hetamsaria