Add information about writting yourself rules, revert no_command changes

thefuck/utils.py

@@ -1,7 +1,10 @@
+from functools import wraps
 import os
 
 
 def which(program):
+    """Returns `program` path or `None`."""
+
     def is_exe(fpath):
         return os.path.isfile(fpath) and os.access(fpath, os.X_OK)
 
@@ -17,3 +20,24 @@ def which(program):
                 return exe_file
 
     return None
+
+
+def wrap_settings(params):
+    """Adds default values to settings if it not presented.
+
+    Usage:
+
+        @wrap_settings({'apt': '/usr/bin/apt'})
+        def match(command, settings):
+            print(settings.apt)
+
+    """
+    def decorator(fn):
+        @wraps(fn)
+        def wrapper(command, settings):
+            for key, val in params.items():
+                if not hasattr(settings, key):
+                    setattr(settings, key, val)
+            return fn(command, settings)
+        return wrapper
+    return decorator