def valid_file?(entry)
      ext = File.extname(entry).gsub(/\./, "").downcase
      File.file?(source.join(entry)) && EXTENSIONS.include?(ext) && entry !~ IGNORE_FILES
    end
def valid_file?(entry)
      ext = File.extname(entry).gsub(/\./, "").downcase
      File.file?(source.join(entry)) && EXTENSIONS.include?(ext) && entry !~ IGNORE_FILES
    end
Check if path is a valid file.