code: def validate_existing_filepath(prefix, suffix=None):
      """Validates existing file in the path constructed from prefix.suffix in case
      prefix is not None"""
      if prefix is not None and prefix:
          io.validate_existing_filepath(
              fix_path(add_suffix(prefix, suffix))
          )
  
imports: from __future__ import print_function
  import argparse
  import os
  import random
  import sys
  import numpy
  import tensorflow
  from nlp_architect.utils import io
  from .None import inference
  from .None import train
  from .gnmt.utils import misc_utils, vocab_utils, evaluation_utils
label_desc: Use image node_id 5 for calling a global function with example usage: validate_existing_filepath(prefix, suffix) without return types