docs: def _set_emails(
              self, emails, global_substitutions=None, is_multiple=False, p=0):
          """Adds emails to the Personalization object
  
          :param emails: An Email or list of Email objects
          :type emails: Email, list(Email)
          :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
          """
          # Send multiple emails to multiple recipients
          if is_multiple is True:
              if isinstance(emails, list):
                  for email in emails:
                      personalization = Personalization()
                      personalization.add_email(email)
                      self.add_personalization(personalization)
              else:
                  personalization = Personalization()
                  personalization.add_email(emails)
                  self.add_personalization(personalization)
              if global_substitutions is not None:
                  if isinstance(global_substitutions, list):
                      for substitution in global_substitutions:
                          for p in self.personalizations:
                              p.add_substitution(substitution)
                  else:
                      for p in self.personalizations:
                          p.add_substitution(global_substitutions)
          else:
              try:
                  personalization = self._personalizations[p]
                  has_internal_personalization = True
              except IndexError:
                  personalization = Personalization()
                  has_internal_personalization = False
  
              if isinstance(emails, list):
                  for email in emails:
                      personalization.add_email(email)
              else:
                  personalization.add_email(emails)
  
              if global_substitutions is not None:
                  if isinstance(global_substitutions, list):
                      for substitution in global_substitutions:
                          personalization.add_substitution(substitution)
                  else:
                      personalization.add_substitution(global_substitutions)
  
              if not has_internal_personalization:
                  self.add_personalization(personalization, index=p)