Fix docstring

Author: icywang86rui

src/sagemaker/estimator.py

@@ -79,6 +79,9 @@ def __init__(self, role, train_instance_count, train_instance_type,
                 using the default AWS configuration chain.
             tags (list[dict]): List of tags for labeling a training job. For more, see
                 https://docs.aws.amazon.com/sagemaker/latest/dg/API_Tag.html.
+            subnets (list[str]): List of subnet ids. If not specified training job will be created without VPC config.
+            security_group_ids (list[str]): List of security group ids. If not specified training job will be created
+                without VPC config.
         """
         self.role = role
         self.train_instance_count = train_instance_count

src/sagemaker/session.py

@@ -228,6 +228,13 @@ def train(self, image, input_mode, input_config, role, job_name, output_config,
                 * instance_type (str): Type of EC2 instance to use for training, for example, 'ml.c4.xlarge'.
                     The key in resource_config is 'InstanceType'.
 
+            vpc_config (dict): Contains values for VpcConfig:
+
+                * subnets (list[str]): List of subnet ids.
+                    The key in vpc_config is 'Subnets'.
+                * security_group_ids (list[str]): List of security group ids.
+                    The key in vpc_config is 'SecurityGroupIds'.
+
             hyperparameters (dict): Hyperparameters for model training. The hyperparameters are made accessible as
                 a dict[str, str] to the training code on SageMaker. For convenience, this accepts other types for
                 keys and values, but ``str()`` will be called to convert them before training.