def incr(self, stat, value=<NUM_LIT:1>, tags=None):
full_stat = self._full_stat(stat)<EOL>for backend in _get_metrics_backends():<EOL><INDENT>backend.incr(full_stat, value=value, tags=tags)<EOL><DEDENT>
Incr is used for counting things.

        :arg string stat: A period delimited alphanumeric key.

        :arg int value: A value to increment the count by. Usually this is 1.

        :arg list-of-strings tags: Each string in the tag consists of a key and
            a value separated by a colon. Tags can make it easier to break down
            metrics for analysis.

            For example ``['env:stage', 'compressed:yes']``.

        For example:

        >>> import markus

        >>> metrics = markus.get_metrics('foo')
        >>> def chop_vegetable(kind):
        ...     # chop chop chop
        ...     metrics.incr('vegetable', value=1)

        You can also use incr to decrement by passing a negative value.