code: def test_aws_session_class_unsigned_noboto3(monkeypatch):
      """AWSSession works without boto3"""
      import rasterio.session
  
      monkeypatch.setenv("AWS_NO_SIGN_REQUEST", "YES")
      monkeypatch.setattr(rasterio.session, "boto3", None)
      assert rasterio.session.boto3 is None
  
      sesh = AWSSession()
      assert sesh.unsigned is True
      assert (
          sesh.get_credential_options()["AWS_NO_SIGN_REQUEST"] == "YES"
      )
      monkeypatch.undo()
  
imports: from unittest import mock
  import pytest
  from rasterio.session import DummySession, AWSSession, Session, OSSSession, GSSession, SwiftSession, AzureSession, parse_bool
label_desc: Use image node_id 8 for calling a global function with example usage: test_aws_session_class_unsigned_noboto3(monkeypatch) without return types