diff --git a/mitmproxy/addons/view.py b/mitmproxy/addons/view.py
index 3a0587b05..2218327c9 100644
--- a/mitmproxy/addons/view.py
+++ b/mitmproxy/addons/view.py
@@ -241,7 +241,7 @@ class View(collections.Sequence):
         self._refilter()
         self.sig_store_refresh.send(self)
 
-    def add(self, f: mitmproxy.flow.Flow) -> bool:
+    def add(self, f: mitmproxy.flow.Flow) -> None:
         """
             Adds a flow to the state. If the flow already exists, it is
             ignored.
@@ -371,6 +371,7 @@ class Focus:
     def index(self) -> typing.Optional[int]:
         if self.flow:
             return self.view.index(self.flow)
+        return None
 
     @index.setter
     def index(self, idx):
diff --git a/mitmproxy/contentviews/__init__.py b/mitmproxy/contentviews/__init__.py
index c7db66904..f57b27c7f 100644
--- a/mitmproxy/contentviews/__init__.py
+++ b/mitmproxy/contentviews/__init__.py
@@ -36,12 +36,14 @@ def get(name: str) -> Optional[View]:
     for i in views:
         if i.name.lower() == name.lower():
             return i
+    return None
 
 
 def get_by_shortcut(c: str) -> Optional[View]:
     for i in views:
         if i.prompt[1] == c:
             return i
+    return None
 
 
 def add(view: View) -> None:
diff --git a/mitmproxy/contentviews/xml_html.py b/mitmproxy/contentviews/xml_html.py
index 0f2ce57df..62fb939fd 100644
--- a/mitmproxy/contentviews/xml_html.py
+++ b/mitmproxy/contentviews/xml_html.py
@@ -128,6 +128,7 @@ def is_inline_text(a: Token, b: Token, c: Token) -> bool:
     if isinstance(a, Tag) and isinstance(b, Text) and isinstance(c, Tag):
         if a.is_opening and "\n" not in b.data and c.is_closing and a.tag == c.tag:
             return True
+    return False
 
 
 def is_inline(prev2: Token, prev1: Token, t: Token, next1: Token, next2: Token) -> bool:
@@ -140,6 +141,7 @@ def is_inline(prev2: Token, prev1: Token, t: Token, next1: Token, next2: Token)
                 return True  # <div></div> (start tag)
         if isinstance(prev1, Tag) and prev1.is_opening and t.is_closing and prev1.tag == t.tag:
             return True  # <div></div> (end tag)
+    return False
 
 
 class ElementStack:
diff --git a/setup.py b/setup.py
index 6f17a62ee..5bf9fa1b7 100644
--- a/setup.py
+++ b/setup.py
@@ -96,7 +96,7 @@ setup(
         'dev': [
             "Flask>=0.10.1, <0.13",
             "flake8>=3.2.1, <3.4",
-            "mypy>=0.471, <0.480",
+            "mypy>=0.471, <0.502",
             "rstcheck>=2.2, <4.0",
             "tox>=2.3, <3",
             "pytest>=3, <3.1",