def prune_dict(my_dict):
    """
    Remove all keys associated to a null value.

    Args:
        my_dict (dict): any dictionary

    Returns:
        pruned_dict (dict): pruned dictionary

    """

    # Start from empty dict
    pruned_dict = dict()

    # Add all entry of dict1 that does not have a null value
    for key in my_dict.keys():

        if my_dict[key] != 0:

            pruned_dict[key] = my_dict[key]

    # Return pruned dict
    return pruned_dict