updated IO wrapper, style, version

setup.py

@@ -18,5 +18,5 @@
     package_dir={"": "src"},
     packages=["cs50"],
     url="https://github.com/cs50/python-cs50",
-    version="9.3.0"
+    version="9.3.1"
 )

src/cs50/__init__.py

@@ -8,6 +8,7 @@
 
 # Import cs50_*
 from .cs50 import get_char, get_float, get_int, get_string
+
 try:
     from .cs50 import get_long
 except ImportError:

src/cs50/cs50.py

@@ -17,7 +17,9 @@
 
 try:
     # Patch formatException
-    logging.root.handlers[0].formatter.formatException = lambda exc_info: _formatException(*exc_info)
+    logging.root.handlers[
+        0
+    ].formatter.formatException = lambda exc_info: _formatException(*exc_info)
 except IndexError:
     pass
 
@@ -37,26 +39,31 @@
 _logger.addHandler(handler)
 
 
-class _flushfile():
+class _Unbuffered:
     """
     Disable buffering for standard output and standard error.
 
-    http://stackoverflow.com/a/231216
+    https://stackoverflow.com/a/107717
+    https://docs.python.org/3/library/io.html
     """
 
-    def __init__(self, f):
-        self.f = f
+    def __init__(self, stream):
+        self.stream = stream
 
-    def __getattr__(self, name):
-        return getattr(self.f, name)
+    def __getattr__(self, attr):
+        return getattr(self.stream, attr)
 
-    def write(self, x):
-        self.f.write(x)
-        self.f.flush()
+    def write(self, b):
+        self.stream.write(b)
+        self.stream.flush()
 
+    def writelines(self, lines):
+        self.stream.writelines(lines)
+        self.stream.flush()
 
-sys.stderr = _flushfile(sys.stderr)
-sys.stdout = _flushfile(sys.stdout)
+
+sys.stderr = _Unbuffered(sys.stderr)
+sys.stdout = _Unbuffered(sys.stdout)
 
 
 def _formatException(type, value, tb):
@@ -78,19 +85,29 @@ def _formatException(type, value, tb):
             lines += line
         else:
             matches = re.search(r"^(\s*)(.*?)(\s*)$", line, re.DOTALL)
-            lines.append(matches.group(1) + colored(matches.group(2), "yellow") + matches.group(3))
+            lines.append(
+                matches.group(1)
+                + colored(matches.group(2), "yellow")
+                + matches.group(3)
+            )
     return "".join(lines).rstrip()
 
 
-sys.excepthook = lambda type, value, tb: print(_formatException(type, value, tb), file=sys.stderr)
+sys.excepthook = lambda type, value, tb: print(
+    _formatException(type, value, tb), file=sys.stderr
+)
 
 
 def eprint(*args, **kwargs):
-    raise RuntimeError("The CS50 Library for Python no longer supports eprint, but you can use print instead!")
+    raise RuntimeError(
+        "The CS50 Library for Python no longer supports eprint, but you can use print instead!"
+    )
 
 
 def get_char(prompt):
-    raise RuntimeError("The CS50 Library for Python no longer supports get_char, but you can use get_string instead!")
+    raise RuntimeError(
+        "The CS50 Library for Python no longer supports get_char, but you can use get_string instead!"
+    )
 
 
 def get_float(prompt):

src/cs50/flask.py

@@ -2,6 +2,7 @@
 import pkgutil
 import sys
 
+
 def _wrap_flask(f):
     if f is None:
         return
@@ -17,10 +18,15 @@ def _wrap_flask(f):
 
     if os.getenv("CS50_IDE_TYPE") == "online":
         from werkzeug.middleware.proxy_fix import ProxyFix
+
         _flask_init_before = f.Flask.__init__
+
         def _flask_init_after(self, *args, **kwargs):
             _flask_init_before(self, *args, **kwargs)
-            self.wsgi_app = ProxyFix(self.wsgi_app, x_proto=1)  # For HTTPS-to-HTTP proxy
+            self.wsgi_app = ProxyFix(
+                self.wsgi_app, x_proto=1
+            )  # For HTTPS-to-HTTP proxy
+
         f.Flask.__init__ = _flask_init_after
 
 
@@ -30,7 +36,7 @@ def _flask_init_after(self, *args, **kwargs):
 
 # If Flask wasn't imported
 else:
-    flask_loader = pkgutil.get_loader('flask')
+    flask_loader = pkgutil.get_loader("flask")
     if flask_loader:
         _exec_module_before = flask_loader.exec_module