docs: def mailto(to, cc=None, bcc=None, subject=None, body=None):
      """
      Generate and run mailto.
  
      :type to: string
      :param to: The recipient email address.
  
      :type cc: string
      :param cc: The recipient to copy to.
  
      :type bcc: string
      :param bcc: The recipient to blind copy to.
  
      :type subject: string
      :param subject: The subject to use.
  
      :type body: string
      :param body: The body content to use.
      """
  
      mailurl = 'mailto:' + str(to)
      if cc is None and bcc is None and subject is None and body is None:
          return str(mailurl)
      mailurl += '?'
      if cc is not None:
          mailurl += 'cc=' + str(cc)
          added = True
      added = False
      if bcc is not None:
          if added is True:
              mailurl += '&'
          mailurl += 'bcc=' + str(cc)
          added = True
      if subject is not None:
          if added is True:
              mailurl += '&'
          mailurl += 'subject=' + str(subject)
          added = True
      if body is not None:
          if added is True:
              mailurl += '&'
          mailurl += 'body=' + str(body)
          added = True
      return mailurl