[nodes] Adds arg0_to_kwargs and kwargs_to_arg0 transformations.

bonobo/_api.py

@@ -1,6 +1,6 @@
 from bonobo.structs import Bag, Graph, Token
 from bonobo.nodes import CsvReader, CsvWriter, FileReader, FileWriter, Filter, JsonReader, JsonWriter, Limit, \
-    PrettyPrinter, PickleWriter, PickleReader, RateLimited, Tee, count, identity, noop
+    PrettyPrinter, PickleWriter, PickleReader, RateLimited, Tee, count, identity, noop, arg0_to_kwargs, kwargs_to_arg0
 from bonobo.strategies import create_strategy
 from bonobo.util.objects import get_name
 
@@ -101,13 +101,15 @@ register_api_group(
     JsonReader,
     JsonWriter,
     Limit,
-    PrettyPrinter,
     PickleReader,
     PickleWriter,
+    PrettyPrinter,
     RateLimited,
     Tee,
+    arg0_to_kwargs,
     count,
     identity,
+    kwargs_to_arg0,
     noop,
 )
 

bonobo/nodes/basics.py

@@ -91,8 +91,22 @@ def noop(*args, **kwargs):  # pylint: disable=unused-argument
 
 
 def arg0_to_kwargs(row):
+    """
+    Transform items in a stream from "arg0" format (each call only has one positional argument, which is a dict-like
+    object) to "kwargs" format (each call only has keyword arguments that represent a row).
+
+    :param row:
+    :return: bonobo.Bag
+    """
     return Bag(**row)
 
 
 def kwargs_to_arg0(**row):
+    """
+    Transform items in a stream from "kwargs" format (each call only has keyword arguments that represent a row) to
+    "arg0" format (each call only has one positional argument, which is a dict-like object) .
+
+    :param **row:
+    :return: bonobo.Bag
+    """
     return Bag(row)