files_in_dir() {
  #function to check if provided virtualenv is not empty
  shopt -s nullglob dotglob;
  files=("$virtualenv_path_arg"/*);
  if (( ${#files[*]} ));then
    return true;
  else
    return false;
  shopt -u nullglob dotglob
  fi
}

another_function {

if [ files_in_dir = true ]

}