docs: def to(self, to_emails, global_substitutions=None, is_multiple=False, p=0):
          """Adds To objects to the Personalization object
  
          :param to_emails: An To or list of To objects
          :type to_emails: To, list(To), str, tuple
          :param global_substitutions: A dict of substitutions for all recipients
          :type global_substitutions: dict
          :param is_multiple: Create a new personilization for each recipient
          :type is_multiple: bool
          :param p: p is the Personalization object or Personalization object
                    index
          :type p: Personalization, integer, optional
          """
          if isinstance(to_emails, list):
              for email in to_emails:
                  if isinstance(email, str):
                      email = To(email, None)
                  if isinstance(email, tuple):
                      email = To(email[0], email[1])
                  self.add_to(email, global_substitutions, is_multiple, p)
          else:
              if isinstance(to_emails, str):
                  to_emails = To(to_emails, None)
              if isinstance(to_emails, tuple):
                  to_emails = To(to_emails[0], to_emails[1])
              self.add_to(to_emails, global_substitutions, is_multiple, p)