Update docs

bigchaindb/backend/mongodb/connection.py

@@ -65,6 +65,11 @@ class MongoDBConnection(Connection):
 
 
 def collection(name):
+    """Return a lazy object that can be used to compose a query.
+
+    Args:
+        name (str): the name of the collection to query.
+    """
     return Lazy()[name]
 
 

bigchaindb/utils.py

@@ -160,8 +160,17 @@ def is_genesis_block(block):
 
 
 class Lazy:
+    """Lazy objects are useful to create chains of methods to
+    execute later.
+
+    A lazy object records the methods that has been called, and
+    replay them when the :py:meth:`run` method is called. Note that
+    :py:meth:`run` needs an object `instance` to replay all the
+    methods that have been recorded.
+    """
 
     def __init__(self):
+        """Instantiate a new Lazy object."""
         self.stack = []
 
     def __getattr__(self, name):
@@ -178,6 +187,12 @@ class Lazy:
         return self
 
     def run(self, instance):
+        """Run the recorded chain of methods on `instance`.
+
+        Args:
+            instance: an object.
+        """
+
         last = instance
 
         for item in self.stack: