docs: def get_certificate(self, filename):
          """
              Return a certificate object by giving the name in the apk file
          """
          pkcs7message = self.get_file(filename)
  
          message, _ = decode(pkcs7message)
          cert = encode(message[1][3])
          # Remove the first identifier·
          # byte 0 == identifier, skip
          # byte 1 == length. If byte1 & 0x80 > 1, we have long format
          #                   The length of to read bytes is then coded
          #                   in byte1 & 0x7F
          cert = cert[2 + (cert[1] & 0x7F) if cert[1] & 0x80 > 1 else 2:]
  
          certificate = x509.load_der_x509_certificate(cert, default_backend())
  
          return certificate