Comments & minor changes

1 files changed, 14 insertions, 6 deletions

diff --git a/mdpoly/abc.py b/mdpoly/abc.py
index 99d9484..8783262 100644
--- a/mdpoly/abc.py
+++ b/mdpoly/abc.py
@@ -23,6 +23,8 @@ class Algebra(Enum):
 class Expr(ABC):
     """ Binary tree to represent a mathematical expression. """
 
+    # --- Properties ---
+
     @property
     def is_leaf(self) -> bool:
         """ Whether an expression is a Leaf of the tree. """
@@ -73,10 +75,17 @@ class Expr(ABC):
         and *right*. If the shape cannot be computed because of an algebraic
         problem raises :py:class:`mdpoly.errors.AlgebraicError`. """
 
+    # --- Magic Methods ---
+
     def __repr__(self):
         name = self.__class__.__qualname__
         return f"{name}(left={self.left}, right={self.right})"
 
+    def __iter__(self) -> Iterable[Expr]:
+        yield from self.children()
+
+    # --- Methods ---
+
     @abstractmethod
     def to_repr(self, repr_type: type, state: State) -> tuple[Repr, State]:
         """ Convert to a concrete representation 
@@ -147,11 +156,7 @@ class Expr(ABC):
 
         return replace_all(self)
 
-    
-    def __iter__(self) -> Iterable[Expr]:
-        yield from self.children()
-
-    # --- Operator overloading ---
+    # --- Private methods ---
 
     @staticmethod
     def _assert_same_algebra(left: Expr, right: Expr) -> None:
@@ -179,10 +184,13 @@ class Expr(ABC):
             return obj
 
         if not isinstance(obj, if_type):
-            raise TypeError(f"Cannot wrap {obj} with type {wrapper_type} because it is not of type {if_type}.")
+            raise TypeError(f"Cannot wrap {obj} with type {wrapper_type} because "
+                            f"it is not of type {if_type}.")
 
         return wrapper_type(obj, *args, **kwargs)
 
+    # --- Operator overloading ---
+
     def __add__(self, other: Any) -> Self:
         raise NotImplementedError