def create_attachment(self, resource_id='', attachment=None, actor_id=None):
        if attachment is None:
            raise BadRequest("Object not present")
        if not isinstance(attachment, Attachment):
            raise BadRequest("Object is not an Attachment")

        attachment.object_id = resource_id if resource_id else ""
        attachment.attachment_size = -1

        attachment_content = None

        if attachment.attachment_type == AttachmentType.BLOB:
            if type(attachment.content) is not str:
                raise BadRequest("Attachment content must be str")
            attachment.attachment_size = len(attachment.content)
            attachment_content = attachment.content
        elif attachment.attachment_type == AttachmentType.ASCII:
            if type(attachment.content) is not str:
                raise BadRequest("Attachment content must be str")
            attachment.attachment_size = len(attachment.content)
            attachment_content = attachment.content
        elif attachment.attachment_type == AttachmentType.OBJECT:
            raise BadRequest("AttachmentType.OBJECT is not supported currently")
        elif attachment.attachment_type == AttachmentType.REFERENCE:
            if not isinstance(attachment.content, basestring):
                raise BadRequest("Attachment content must be binary string")
            attachment.attachment_size = len(attachment.content)
            attachment_content = attachment.content
        else:
            raise BadRequest("Unknown attachment-type: %s" % attachment.attachment_type)

        attachment.content = ''
        content = dict(data=attachment_content, content_type=attachment.content_type)

        att_id, _ = self.create(attachment, attachments={self.DEFAULT_ATTACHMENT_NAME: content}, actor_id=actor_id)

        if resource_id:
            self.create_association(resource_id, PRED.hasAttachment, att_id)

        return att_id
Creates an Attachment resource from given argument and associates it with the given resource.
dataset/ETHPy150Open ooici/pyon/pyon/ion/resregistry.py/ResourceRegistry.create_attachment