* ``compare``. Compares attribute being validated with some other attribute
value. Supported comparison operations include: ``equal``. See
+* ``regex``. Search for regular expression pattern. Initialized with
+ ``regex`` as a regular expression pattern or a pre-compiled regular
+ expression. See :py:class:`~wheezy.validation.rules.RegexRule`.
+* ``slug``. Ensures only letters, numbers, underscores or hyphens. See
+* ``email``. Ensures a valid email. See
+* ``range``. Ensures value is in range defined by this rule. Works with any
+ numbers including int, float, decimal, etc. Supported range attributes
+ include: ``min``, ``max``. See
'username': [required(message_template='Required field')]
+Every rule supports ``message_template`` argument during rule declaration.