[
  "perplexity",
  "burst_mean",
  "burst_std",
  "burst_max",
  "burst_min",
  "burst_range",
  "num_words",
  "num_chars",
  "num_sentences",
  "avg_word_len",
  "avg_sent_len",
  "lexical_diversity",
  "punct_ratio",
  "caps_ratio",
  "flesch_reading",
  "flesch_grade"
]