code: def test_parse_parts_with_multiple_attachments(self):
      email_parts = [
          {
              "mimeType": "multipart/mixed",
              "parts": [
                  {
                      "mimeType": "multipart/alternative",
                      "parts": [
                          {
                              "mimeType": "text/plain",
                              "body": {
                                  "data": "VGhpcyBpcyB0aGUgcGxhaW4gdGV4dCBib2R5IG9mIHRoZSBlbWFpbC4="
                              },
                          },
                          {
                              "mimeType": "text/html",
                              "body": {
                                  "data": "PGh0bWw+CiAgICA8Ym9keT4KICAgICAgPHA+"
                                  "VGhpcyBpcyB0aGUgSFRNTCBib2R5IG9mIHRoZSBlbWFpb"
                                  "C4gPC9wPgogICAgPC9ib2R5PjwvaHRtbD4="
                              },
                          },
                      ],
                  },
                  {
                      "mimeType": "application/pdf",
                      "filename": "example.pdf",
                      "body": {"attachmentId": "<<attachment_id>>"},
                  },
                  {
                      "mimeType": "application/pdf",
                      "filename": "example2.pdf",
                      "body": {"attachmentId": "<<attachment_id2>>"},
                  },
              ],
          }
      ]
      attachments = []
      email_body = self.handler._parse_parts(email_parts, attachments)
      expected_body = "This is the plain text body of the email."
      expected_attachments = [
          {
              "filename": "example.pdf",
              "mimeType": "application/pdf",
              "attachmentId": "<<attachment_id>>",
          },
          {
              "filename": "example2.pdf",
              "mimeType": "application/pdf",
              "attachmentId": "<<attachment_id2>>",
          },
      ]
      self.assertEqual(email_body, expected_body)
      self.assertEqual(attachments, expected_attachments)
  
imports: from mindsdb.api.executor.data_types.response_type import RESPONSE_TYPE
  from mindsdb.integrations.handlers.gmail_handler.gmail_handler import GmailHandler
  from mindsdb.integrations.handlers.gmail_handler.gmail_handler import EmailsTable
  from google.oauth2.credentials import Credentials
  from mindsdb_sql import parse_sql
  import unittest
  from unittest.mock import Mock, patch
  from unittest import mock
label_desc: Use image node_id 9 for calling the GmailHandlerTest obj's underlying member method code with example usage: obj.test_parse_parts_with_multiple_attachments() without return types