Loading countersigns gets all very slow

[mari-ano]

Hi there!
I'm using your modules for a project and I must say they really work well.
But, I think I have encountered what could be a problem: everything is smooth and fast up to when you load in the cms ContentInfo a structure with counter_signature as the type in the ungned_attrs of the SingerInfo.
I wrote a small sample code with a recursive call that does nothing but print out a couple of random values.
If you run the code with a cms that only has "parallel" SignerInfo (parallele.p7m) it runs fast, but if you run it with a cms thas has SignerInfos iside other SignerInfo, i,e, counter signatures (controfirme.p7m), it runs sensitively slower. The number of SignerInfo object is the same in both cases.
This is a small code and the delay is evident but not so important. I'm running a project with a larger code and the delay can get up to 60-70 seconds.
I hope you can help me in finding a solution.

from asn1crypto import cms, tsp
import os

scriptdir = os.path.dirname(os.path.abspath(__file__)) + '/'
k = 0

def print_data(signer):
    global k
    a = k = k + 1
    print('Signer #{:02} - Serial n.: {}'.format(a, signer['sid'].native['serial_number']))
    print('Signer #{:02} - Algorithm: {}'.format(a, signer['signature_algorithm'].native['algorithm']))

    for unsigned_attr in signer['unsigned_attrs']:
        if unsigned_attr.native['type'] == 'counter_signature':
            for countersigner_info in unsigned_attr['values']:
                print_data(countersigner_info)

content_info = cms.ContentInfo.load(open(scriptdir + 'countersign.p7m', 'rb').read())
for signer_info in content_info['content']['signer_infos']:
    print_data(signer_info)

Thanks in advance

test_data.zip

[mari-ano]

Ok! I got an hint!
Everything goes smooth if you don't import the tsp module...