'Return the current bottom-level bound segment dictionary.
This property returns the current bottom-level bound segment
dictionary, or None if the port is unbound. For a bound port,
bottom_bound_segment is equivalent to
binding_levels[-1][BOUND_SEGMENT], and returns the segment
whose binding supplied the port\'s binding:vif_type and
binding:vif_details attribute values.'

@abc.abstractproperty
def bottom_bound_segment(self):

    pass
