def __init__(self, obj_to_ind=None, ind_to_obj=None, next_ind=0):
        """Create a new EquivSet object. Optional keyword arguments are for
        internal use only.
        """
        # obj_to_ind maps object to equivalence index (sometimes also called
        # equivalence class) is a non-negative number that uniquely identifies
        # a set of objects that are equivalent.
        self.obj_to_ind = obj_to_ind if obj_to_ind else {}
        # ind_to_obj maps equivalence index to a list of objects.
        self.ind_to_obj = ind_to_obj if ind_to_obj else {}
        # next index number that is incremented each time a new equivalence
        # relation is created.
        self.next_ind = next_ind
Create a new EquivSet object. Optional keyword arguments are for
        internal use only.
        
numba/parfors/array_analysis.py