diff --git a/datasette/app.py b/datasette/app.py
index 1a20dbd0..3793cd55 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -699,9 +699,7 @@ class Datasette:
             if hook:
                 for ct in hook:
                     if ct.name in self._column_types:
-                        raise StartupError(
-                            f"Duplicate column type name: {ct.name}"
-                        )
+                        raise StartupError(f"Duplicate column type name: {ct.name}")
                     self._column_types[ct.name] = ct
 
         for hook in pm.hook.prepare_jinja2_environment(
@@ -977,15 +975,16 @@ class Datasette:
                         logging.warning(
                             "column_types config references unknown type %r "
                             "for %s.%s.%s",
-                            col_type, db_name, table_name, col_name,
+                            col_type,
+                            db_name,
+                            table_name,
+                            col_name,
                         )
                     await self.set_column_type(
                         db_name, table_name, col_name, col_type, config
                     )
 
-    async def get_column_type(
-        self, database: str, resource: str, column: str
-    ) -> tuple:
+    async def get_column_type(self, database: str, resource: str, column: str) -> tuple:
         """
         Return (column_type_name, config_dict) for a specific column,
         or (None, None) if no column type is assigned.
@@ -1001,9 +1000,7 @@ class Datasette:
         ct, config = rows[0]
         return (ct, json.loads(config) if config else None)
 
-    async def get_column_types(
-        self, database: str, resource: str
-    ) -> dict:
+    async def get_column_types(self, database: str, resource: str) -> dict:
         """
         Return {column_name: (column_type_name, config_dict_or_None)}
         for all columns with assigned types on the given resource.
@@ -1019,16 +1016,25 @@ class Datasette:
         }
 
     async def set_column_type(
-        self, database: str, resource: str, column: str,
-        column_type: str, config: dict = None
+        self,
+        database: str,
+        resource: str,
+        column: str,
+        column_type: str,
+        config: dict = None,
     ) -> None:
         """Assign a column type. Overwrites any existing assignment."""
         await self.get_internal_database().execute_write(
             """INSERT OR REPLACE INTO column_types
                (database_name, resource_name, column_name, column_type, config)
                VALUES (?, ?, ?, ?, ?)""",
-            [database, resource, column, column_type,
-             json.dumps(config) if config else None],
+            [
+                database,
+                resource,
+                column,
+                column_type,
+                json.dumps(config) if config else None,
+            ],
         )
 
     async def remove_column_type(
diff --git a/datasette/hookspecs.py b/datasette/hookspecs.py
index ec779659..86cd529e 100644
--- a/datasette/hookspecs.py
+++ b/datasette/hookspecs.py
@@ -56,8 +56,16 @@ def publish_subcommand(publish):
 
 @hookspec
 def render_cell(
-    row, value, column, table, pks, database, datasette, request,
-    column_type, column_type_config
+    row,
+    value,
+    column,
+    table,
+    pks,
+    database,
+    datasette,
+    request,
+    column_type,
+    column_type_config,
 ):
     """Customize rendering of HTML table cell values"""
 
diff --git a/datasette/views/row.py b/datasette/views/row.py
index 0702368d..d1713d4d 100644
--- a/datasette/views/row.py
+++ b/datasette/views/row.py
@@ -193,18 +193,27 @@ class RowView(DataView):
                         ct_class = self.ds.get_column_type_class(ct_name)
                         if ct_class:
                             candidate = await ct_class.render_cell(
-                                value=value, column=column, table=table,
-                                database=database, datasette=self.ds,
-                                request=request, config=ct_config,
+                                value=value,
+                                column=column,
+                                table=table,
+                                database=database,
+                                datasette=self.ds,
+                                request=request,
+                                config=ct_config,
                             )
                             if candidate is not None:
                                 plugin_display_value = candidate
                     if plugin_display_value is None:
                         for candidate in pm.hook.render_cell(
-                            row=row, value=value, column=column,
-                            table=table, pks=resolved.pks,
-                            database=database, datasette=self.ds,
-                            request=request, column_type=ct_name,
+                            row=row,
+                            value=value,
+                            column=column,
+                            table=table,
+                            pks=resolved.pks,
+                            database=database,
+                            datasette=self.ds,
+                            request=request,
+                            column_type=ct_name,
                             column_type_config=ct_config,
                         ):
                             candidate = await await_me_maybe(candidate)
@@ -366,6 +375,7 @@ class RowUpdateView(BaseView):
 
         # Validate column types
         from datasette.views.table import _validate_column_types
+
         ct_errors = await _validate_column_types(
             self.ds, resolved.db.name, resolved.table, [update]
         )
diff --git a/docs/internals.rst b/docs/internals.rst
index f1064b8b..e9c6454e 100644
--- a/docs/internals.rst
+++ b/docs/internals.rst
@@ -944,9 +944,7 @@ Returns a dictionary mapping column names to ``(column_type_name, config)`` tupl
 
 .. code-block:: python
 
-    ct_map = await datasette.get_column_types(
-        "mydb", "mytable"
-    )
+    ct_map = await datasette.get_column_types("mydb", "mytable")
     # {"email_col": ("email", None), "site": ("url", None)}
 
 .. _datasette_set_column_type:
@@ -970,8 +968,11 @@ Assigns a column type to a column. Overwrites any existing assignment for that c
 .. code-block:: python
 
     await datasette.set_column_type(
-        "mydb", "mytable", "location", "point",
-        config={"srid": 4326}
+        "mydb",
+        "mytable",
+        "location",
+        "point",
+        config={"srid": 4326},
     )
 
 .. _datasette_remove_column_type:
diff --git a/docs/plugin_hooks.rst b/docs/plugin_hooks.rst
index b25403b3..052c17b0 100644
--- a/docs/plugin_hooks.rst
+++ b/docs/plugin_hooks.rst
@@ -1013,8 +1013,14 @@ Return a list of :ref:`ColumnType <column_types>` instances to register custom c
 
     class ColorColumnType(ColumnType):
         async def render_cell(
-            self, value, column, table, database,
-            datasette, request, config
+            self,
+            value,
+            column,
+            table,
+            database,
+            datasette,
+            request,
+            config,
         ):
             if value:
                 return markupsafe.Markup(