code: def test_set_s3_credentials_impl():
      aws_creds_prefix = (
          os.environ["AWS_CREDS_PREFIX"]
          if "AWS_CREDS_PREFIX" in os.environ
          else ""
      )
      access_key_id = os.environ[aws_creds_prefix + "AWS_ACCESS_KEY_ID"]
      secret_access_key = os.environ[
          aws_creds_prefix + "AWS_SECRET_ACCESS_KEY"
      ]
  
      assert access_key_id is not None
      assert secret_access_key is not None
  
      # Check that we cannot connect without setting credentials (this will only work if prefix is defined,
      # otherwise H2O will just pick it up from environment variables)
      if aws_creds_prefix:
          try:
              h2o.import_file(
                  "s3://test.0xdata.com/h2o-unit-tests/iris.csv"
              )
              assert False
          except Exception as e:
              assert type(e) is h2o.exceptions.H2OServerError
              assert (
                  e.args[0].find(
                      "Error: Unable to load AWS credentials from any provider in the chain"
                  )
                  != -1
              )
              print(
                  "Validated that setting credentials using set_s3_credentials is necessary for import from S3 to work"
              )
  
      # Now set the credentials
      # 1. Check PersistS3
      set_s3_credentials(access_key_id, secret_access_key)
      file = h2o.import_file(
          "s3://test.0xdata.com/h2o-unit-tests/iris.csv"
      )
      assert file is not None
  
      # 2. Check S3A (Using PersistHdfs)
      file = h2o.import_file(
          "s3a://test.0xdata.com/h2o-unit-tests/iris.csv"
      )
      assert file is not None
  
      access_key_id = "abcd"
      secret_access_key = "abcd"
      set_s3_credentials(access_key_id, secret_access_key)
      try:
          h2o.import_file(
              "s3://test.0xdata.com/h2o-unit-tests/iris.csv"
          )
          assert False
      except Exception as e:
          assert type(e) is h2o.exceptions.H2OServerError
          assert (
              e.args[0].find(
                  "Error: The AWS Access Key Id you provided does not exist in our records. (Service: Amazon S3; Status Code: 403; Error Code: InvalidAccessKeyId;"
              )
              != -1
          )
  
imports: import h2o
  import os
  from h2o.exceptions import H2OValueError
  from h2o.persist import set_s3_credentials
  from h2o.persist import remove_s3_credentials
  from tests import pyunit_utils
label_desc: Use image node_id 2 for calling a global function with example usage: test_set_s3_credentials_impl() without return types