GnuTLS recv error

import pycurl
class Someclass:
       def __init__(self, trycount=0, cookie_file=None, log_file=None):

                pycurl.global_init(pycurl.GLOBAL_ALL);

                #debugging
                self.debug = True;
                self.curl = pycurl.Curl()

                self.curl.setopt(pycurl.FOLLOWLOCATION, 1)
                self.curl.setopt(pycurl.MAXREDIRS, 5)

                if self.debug:
                        self.curl.setopt(pycurl.VERBOSE, 1)

       def perform(self, url, cainfo=None, sslcert=None):
                self.curl.setopt(pycurl.URL, url);

          

                if not cainfo==None:
                        self.curl.setopt(pycurl.CAINFO, cainfo);
                        self.curl.setopt(pycurl.SSL_VERIFYHOST, 1);

                if not sslcert==None:
                        self.curl.setopt(pycurl.SSLCERT, sslcert);
                        self.curl.setopt(pycurl.SSLCERTTYPE, 'PEM');

                        #в бубунте работало без этого
                        #self.curl.setopt(pycurl.SSLKEY, sslcert);
                        #self.curl.setopt(pycurl.SSLKEYTYPE, 'PEM');


                        self.curl.setopt(pycurl.SSL_SESSIONID_CACHE, 0);
                        self.curl.setopt(pycurl.SSL_VERIFYPEER, 0);

              
                self.curl.perform();

a = Someclass();
a.perform('https://www.somesite.net', cainfo='data/cert/somesiteca.crt', sslcert='data/cert/cert.pem'):

* gnutls_handshake() failed: Decryption has failed.
* GnuTLS recv error (-10): The specified session has been invalidated for some reason.