(self, fn, *facets)
:param fn: The function to apply. For each matching document, this
            function will be called with the values of the given facets as
            arguments.
        :param facets: One or more :class:`FacetType` objects. These facets are
            used to compute facet value(s) for a matching document, and then the
            value(s) is/are passed to the function.
:param fn: The function to apply. For each matching document, this
            function will be called with the values of the given facets as
            arguments.
        :param facets: One or more :class:`FacetType` objects. These facets are
            used to compute facet value(s) for a matching document, and then the
            value(s) is/are passed to the function.
: param fn : The function to apply . For each matching document this function will be called with the values of the given facets as arguments . : param facets : One or more : class : FacetType objects . These facets are used to compute facet value ( s ) for a matching document and then the value ( s ) is / are passed to the function .
def __init__(self, fn, *facets):
        """
        :param fn: The function to apply. For each matching document, this
            function will be called with the values of the given facets as
            arguments.
        :param facets: One or more :class:`FacetType` objects. These facets are
            used to compute facet value(s) for a matching document, and then the
            value(s) is/are passed to the function.
        """
        self.fn = fn
        self.facets = facets
        self.maptype = None
def __init__ ( self , fn , * facets ) : self . fn = fn self . facets = facets self . maptype = None