Adds a Bcc object to the Personalization object

        :param to_emails: An Bcc object
        :type to_emails: Bcc
        :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

def add_bcc(
            self,
            bcc_email,
            global_substitutions=None,
            is_multiple=False,
            p=0):
        """Adds a Bcc object to the Personalization object

        :param to_emails: An Bcc object
        :type to_emails: Bcc
        :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(bcc_email, str):
            bcc_email = Bcc(bcc_email, None)
        if isinstance(bcc_email, tuple):
            bcc_email = Bcc(bcc_email[0], bcc_email[1])
        if isinstance(bcc_email, Email):
            p = bcc_email.personalization
        self._set_emails(
            bcc_email,
            global_substitutions,
            is_multiple=is_multiple,
            p=p)