code: def authenticate(self, username=None, password=None):
          
  
          u = self.username
          p = self.password
          if username and password:
              u = username
              p = password
  
          client = self.client()
          query = client.authenticated_query(username=u, password=p)
          res = client.post(query)
          ofx = BeautifulSoup(res, 'lxml')
  
          sonrs = ofx.find('sonrs')
          code = int(sonrs.find('code').contents[0].strip())
  
          try:
              status = sonrs.find('message').contents[0].strip()
          except Exception:
              status = ''
  
          if code == 0:
              return 1
  
          raise ValueError(status)
docs: Test the authentication credentials
  
          Raises a ``ValueError`` if there is a problem authenticating
          with the human readable reason given by the institution.
  
          :param username: optional username (use self.username by default)
          :type username: string or None
          :param password: optional password (use self.password by default)
          :type password: string or None