Specify the position of a boundary between two coordinates.

Arguments: o position - The start position of the boundary. o extension - The range to the other position of a boundary.

This specifies a coordinate which is found between the two positions. So this allows us to deal with a position like ((1^2)..100). To represent that with this class we set position as 1 and the extension as 1.

__init__ (
        self,
        position,
        extension=0,
        )

__str__ ( self )