MultiGrid cell object: set or list?

[peteretchn]

The mesa space.py script contains the following for MultiGrid:
the cell object default value is an empty list [], but is documented and type-hinted as a set. Which should it be?

around line 523:

class MultiGrid(Grid):
    """Grid where each cell can contain more than one object.
    Grid cells are indexed by [x][y], where [0][0] is assumed to be at
    bottom-left and [width-1][height-1] is the top-right. If a grid is
    toroidal, the top and bottom, and left and right, edges wrap to each other.
    Each grid cell holds a set object.
    Properties:
        width, height: The grid's width and height.
        torus: Boolean which determines whether to treat the grid as a torus.
        grid: Internal list-of-lists which holds the grid cells themselves.
    Methods:
        get_neighbors: Returns the objects surrounding a given cell.
    """

    @staticmethod
    def default_val() -> Set[Agent]:
        """ Default value for new cell elements. """
        return []

[Corvince]

Good catch. It used to be a set, but it was changed to a List to enable reproducible behaviour (set order is unpredictable in Python)

Documentation and type hint should be updated