From 80692706e4e136b9ef843d3af555c9913c32c5a8 Mon Sep 17 00:00:00 2001
From: Jason Manuel <jama.indo@hotmail.com>
Date: Sat, 19 Oct 2024 19:14:15 -0700
Subject: [PATCH] Add docstrings for Environment and Substitutions

---
 concat/typecheck/env.py           | 2 ++
 concat/typecheck/substitutions.py | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/concat/typecheck/env.py b/concat/typecheck/env.py
index 0382511..34dce07 100644
--- a/concat/typecheck/env.py
+++ b/concat/typecheck/env.py
@@ -18,6 +18,8 @@
 
 
 class Environment(Mapping[str, 'Type']):
+    """A map from names in a typing context to the types of those names."""
+
     def __init__(self, env: Optional[Mapping[str, Type]] = None) -> None:
         self._env = env or {}
         self._sub_cache = dict[int, Environment]()
diff --git a/concat/typecheck/substitutions.py b/concat/typecheck/substitutions.py
index 0010602..3f5ae8f 100644
--- a/concat/typecheck/substitutions.py
+++ b/concat/typecheck/substitutions.py
@@ -33,6 +33,8 @@ def apply_substitution(self, sub: 'Substitutions') -> _Result:
 
 
 class Substitutions(Mapping['Variable', 'Type']):
+    """Substitutions of type variables with types."""
+
     __next_id = 0
 
     def __init__(