class_docstr: http://boto3.readthedocs.io/en/latest/reference/services/lambda.html
docstr: Publish a new version of the mock Lambda function.
docstr_tok: ["Publish","a","new","version","of","the","mock","Lambda","function","."]
code: def publish_version(self, **kwargs):
      """Publish a new version of the mock Lambda function."""
      # Test error handling
      if self.throw_exception:
          raise ClientError({"Error": {}}, "test")
  
      function_name = kwargs.get("FunctionName")
      code_sha_256 = kwargs.get("CodeSha256")
      description = kwargs.get("Description")
  
      return {
          "FunctionName": function_name,
          "FunctionArn": "arn:aws:lambda:region:account-id:function:{}".format(
              function_name
          ),
          "Runtime": "python3.7",
          "Role": "string",
          "Handler": "main.handler",
          "CodeSize": 128,
          "Description": description,
          "Timeout": 60,
          "MemorySize": 128,
          "LastModified": "string",
          "CodeSha256": code_sha_256,
          "Version": self.current_version + 1,
      }
  
imports: from datetime import datetime
  import uuid
  from io import BytesIO
  import zipfile
  import boto3
  from botocore.exceptions import ClientError
  from streamalert.shared.helpers.aws_api_client import AwsS3
label_desc: Use image node_id 2 for calling the MockLambdaClient obj's underlying member method code with example usage: obj.publish_version() and returns: dict