\class{Command} class from \refmodule{distutils.cmd}. New commands
may directly inherit from \class{Command}, while replacements often
derive from \class{Command} indirectly, directly subclassing the
-command they are replacing. Commands are not required to derive from
-\class{Command}, but must implement the interface documented as part
-of that class.
+command they are replacing. Commands are required to derive from
+\class{Command}.
%\section{Extending existing commands}