Add untested has_option

qutebrowser/config/config.py

@@ -160,6 +160,10 @@ class Config:
             lines.append(keyval)
         return lines
 
+    def has_option(section, option):
+        """Returns True if option is in section."""
+        return option in self.config[section]
+
     @cmdutils.register(instance='config', completion=['setting'])
     def get(self, section, option, fallback=_UNSET, raw=False):
         """Get the value from a section/option.

qutebrowser/config/sections.py

@@ -85,6 +85,10 @@ class KeyValue:
         """Get boolean state."""
         return bool(self.values)
 
+    def __contains__(self, key):
+        """Return whether the section contains a given key."""
+        return key in self.values
+
     def items(self):
         """Get dict item tuples."""
         return self.values.items()
@@ -164,6 +168,11 @@ class ValueList:
         self.update_valdict()
         return bool(self.valdict)
 
+    def __contains__(self, key):
+        """Return whether the section contains a given key."""
+        self.update_valdict()
+        return key in self.valdict
+
     def items(self):
         """Get dict items."""
         self.update_valdict()