API comment copyedit

pmkoalas/models/petrinet.py

@@ -210,12 +210,9 @@ def __repr__(self) -> str:
 
 class LabelledPetriNet:
     """
-    This is a data structure for a class of Petri Nets.
-    This class consists of places, transitions and directed arcs 
-    between them.
-    The class contract implies that places and transitions have 
-    labels/names and identifiers. Each instance of this class, 
-    has a name or title for the net.
+    A labelled Petri Net. It consists of places, transitions and directed arcs 
+    between them.  Places and transitions have labels (names) and identifiers. 
+    The net is also named.
     """
 
     def __init__(self, places:Iterable[Place], transitions:Iterable[Transition],
@@ -313,10 +310,9 @@ def __str__(self) -> str:
 
 class BuildablePetriNet(LabelledPetriNet):
     """
-    This class allows for the builder design pattern to be used
-    for constructing a petri net. It allows for users to quickly
-    add places, transitions and arcs through a single chain of
-    method calls. See usage below.
+    Allows for the builder design pattern to be used for constructing a 
+    Petri net. Users can add places, transitions and arcs through a single 
+    chain of method calls. See usage below.
 
     Usage
     -----