'Find a node in the zone, possibly creating it.
@param name: the name of the node to find
@type name: dns.name.Name object or string
@param create: should the node be created if it doesn\'t exist?
@type create: bool
@raises KeyError: the name is not known and create was not specified.
@rtype: dns.node.Node object'

def find_node(self, name, create=False):

    name = self._validate_name(name)
    node = self.nodes.get(name)
    if (node is None):
        if (not create):
            raise KeyError
        node = self.node_factory()
        self.nodes[name] = node
    return node
