Add documentation on the available iterators.
-"""
-Read a KGTK node or edge file in TSV format.
+"""Read a KGTK node or edge file in TSV format.
+
+Normally, results are obtained as rows of string values obtained by iteration
+on the KgtkReader object. Alternative iterators are available to return the results
+as:
+
+ * concise_rows: lists of strings with empty fields converted to None
+ * kgtk_values: lists of KgtkValue objects
+ * concise_kgtk_values: lists of KgtkValue objects with empty fields converted to None
+ * dicts: dicts of strings
+ * dicts(concise=True): dicts of strings with empty fields omitted
+ * kgtk_value_dicts: dicts of KgtkValue objects
+ * kgtk_value_dicts(concise=True): dicts of KgtkValue objects with empty fields omitted
TODO: Add support for alternative envelope formats, such as JSON.
+
"""
from argparse import ArgumentParser
