Temporarily restore 3.6.0 support

.pre-commit-config.yaml

@@ -11,9 +11,10 @@ repos:
     -   id: name-tests-test
     -   id: requirements-txt-fixer
 -   repo: https://gitlab.com/pycqa/flake8
-    rev: 3.7.8
+    rev: 3.7.9
     hooks:
     -   id: flake8
+        additional_dependencies: [flake8-typing-imports==1.7.0]
 -   repo: https://github.com/pre-commit/mirrors-autopep8
     rev: v1.4.4
     hooks:
@@ -33,7 +34,3 @@ repos:
     hooks:
     -   id: pyupgrade
         args: [--py36-plus]
--   repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.730
-    hooks:
-    -   id: mypy

babi.py

@@ -137,19 +137,28 @@ class Margin(NamedTuple):
     header: bool
     footer: bool
 
-    @property
-    def body_lines(self) -> int:
+
+@property
+def body_lines(self) -> int:
     return curses.LINES - self.header - self.footer
 
-    @property
-    def page_size(self) -> int:
+
+Margin.body_lines = body_lines
+
+
+@property
+def page_size(self) -> int:
     if self.body_lines <= 2:
         return 1
     else:
         return self.body_lines - 2
 
-    @classmethod
-    def from_screen(cls, screen: 'curses._CursesWindow') -> 'Margin':
+
+Margin.page_size = page_size
+
+
+@classmethod
+def from_screen(cls, screen: 'curses._CursesWindow') -> 'Margin':
     if curses.LINES == 1:
         return cls(header=False, footer=False)
     elif curses.LINES == 2:
@@ -158,6 +167,9 @@ class Margin(NamedTuple):
         return cls(header=True, footer=True)
 
 
+Margin.from_screen = from_screen
+
+
 def _get_color_pair_mapping() -> Dict[Tuple[int, int], int]:
     ret = {}
     i = 0