class_docstr: Factory for ensuring a directory exists
class_docstr_tok: ["Factory","for","ensuring","a","directory","exists"]
code: def __call__(self, value):
      if os.path.isdir(value):
          return value
  
      raise ArgumentTypeError("'{}' is not a directory".format(value))
  
imports: from abc import abstractmethod
  from argparse import _AppendAction, Action, ArgumentTypeError, RawDescriptionHelpFormatter
  import os
  import textwrap
  from streamalert.apps.config import AWS_RATE_RE, AWS_RATE_HELPER
label_desc: Use image node_id 1 for calling the DirectoryType obj's underlying member method code with example usage: obj.__call__(value) and returns: value