code: def get_base_url(html: str) -> str:
      
      forms = BeautifulSoup(html, 'html.parser').find_all('form')
      if not forms:
          raise VVKBaseUrlException('Form for login not found')
      elif len(forms) > 1:
          raise VVKBaseUrlException('More than one login form found')
      login_url = forms[0].get('action')
      if not login_url:
          raise VVKBaseUrlException('No action tag in form')
      return login_url
docs: Search for login url from VK login page