diff --git a/aggen.py b/aggen.py
index 7932c34..269bf4d 100644
--- a/aggen.py
+++ b/aggen.py
@@ -47,13 +47,15 @@ class GenResult:
         for name, rules in self.parse_rules.items():
             n = name.lstrip("?")
             for equation in rules:
-                code = textwrap.dedent(f"""
+                code = textwrap.dedent(
+                    f"""
                     def {equation.name}(self, items: Any) -> Thunk[{equation.ty}]:
                         def inner() -> {equation.ty}:
                             res = {equation.ty}()
                             return res
                         return Thunk(inner)
-                """)
+                """
+                )
                 s.append(code)
         if not s:
             s = ["pass"]
diff --git a/agruntime.tmpl.py b/agruntime.tmpl.py
index f2c72f2..bfa80ee 100644
--- a/agruntime.tmpl.py
+++ b/agruntime.tmpl.py
@@ -6,33 +6,47 @@ import re
 from typing import Generic, TypeVar, Optional, Callable, Dict, Any
 from lark import Lark, Transformer
 
-T = TypeVar('T')
-builtins: Dict[str, Any] = {{
-    "parseInt": lambda s: int(s)
-}}
+T = TypeVar("T")
+builtins: Dict[str, Any] = {{"parseInt": lambda s: int(s)}}
+
 
 class Thunk(Generic[T]):
-    ''' A thunk represents a value that may be computed lazily. '''
+    """A thunk represents a value that may be computed lazily."""
+
     value: Optional[T]
+
     def __init__(self, func: Callable[[], T]):
         self.func = func
         self.value = None
+
     def get(self) -> T:
         if self.value is None:
             self.value = self.func()
         return self.value
 
-parser = Lark('''
+
+parser = Lark(
+    """
 {pd}
-''', parser='lalr', start={starts}, debug=True)
+""",
+    parser="lalr",
+    start={starts},
+    debug=True,
+)
 
 {ex}
 
-class Trans(Transformer[None]): {transdef}
+
+class Trans(Transformer[None]):
+    {transdef}
+
 
 __agNonterminals = {ntmap}
+
+
 def parse(input: str, start: Optional[str] = None) -> Any:
-    if start is not None: start = __agNonterminals[start]
+    if start is not None:
+        start = __agNonterminals[start]
     tree = parser.parse(input, start)
     trans = Trans()
     res = trans.transform(tree)