Filter the paragraphs with at least words, nltk, in python

Question

I am learning nltk and I have segmented the novels into paragraphs. What should I do then to filter each author's list so that only paragraphs with at least 30 words are kept? I have gutenberg.words but it failed.

# Load the corpus
from nltk.corpus import gutenberg

# List files available in this corpus
print(gutenberg.fileids())

Austen = gutenberg.paras('austen-emma.txt') + \
             gutenberg.paras('austen-persuasion.txt') + \
             gutenberg.paras('austen-sense.txt')

Shakespeare = gutenberg.paras('shakespeare-caesar.txt') + \
             gutenberg.paras('shakespeare-hamlet.txt') + \
             gutenberg.paras('shakespeare-macbeth.txt')

gutenberg.words(Austen)