Add param description

nltk/corpus/reader/wordnet.py

@@ -327,12 +327,16 @@ def _related(self, relation_symbol):
         """Returns the lemma's relation targets for the given relation_symbol.
         Includes both the lemma ("lexical") relations and the synset ("semantic") relations.
 
-        The in_topic_domain() relation (-c) is hybrid, becuse a few lemmas have
+        The in_topic_domain() relation (-c) is hybrid, because a few lemmas have
         both lemma and synset targets. For ex:
 
         >>> from nltk.corpus import wordnet as wn
         >>> print(wn.lemmas("insect")[0].in_topic_domains())
         [Lemma('chirpy.a.01.chirpy'), Synset('holometabolism.n.01')]
+
+        :param relation_symbol: pointer symbol denoting a WordNet relation
+        :type relation_symbol: string
+        :return: list of target lemmas and/or synsets
         """
         get_synset = self._wordnet_corpus_reader.synset_from_pos_and_offset
         ssrels = self._synset._related(relation_symbol)