docs: def files_in_dir(dirpath, wildcard="*", startpath=None):
      """
      Function generates list of files from specific dir
  
      files_in_dir(dirpath, wildcard="*.*", startpath=None)
  
      dirpath: required directory
      wilcard: mask for files
      startpath: start for relative path
  
      Example
      files_in_dir('medical/jatra-kiv','*.dcm', '~/data/')
      """
  
      import glob
  
      filelist = []
  
      if startpath is not None:
          completedirpath = os.path.join(startpath, dirpath)
      else:
          completedirpath = dirpath
  
      if os.path.exists(completedirpath):
          logger.info('completedirpath = ' + completedirpath)
  
      else:
          logger.error('Wrong path: ' + completedirpath)
          raise Exception('Wrong path : ' + completedirpath)
  
      for infile in glob.glob(os.path.join(completedirpath, wildcard)):
          filelist.append(infile)
  
      if len(filelist) == 0:
          logger.error('No required files in path: ' + completedirpath)
          raise Exception('No required file in path: ' + completedirpath)
  
      return filelist