def get_deletions_x(parsed_mutations, max_mutations_per_pos_dict):
    """Get x coordinates of deletion markers to overlay in heatmap.

    These are the linear x coordinates used in the Plotly graph object.
    i.e., the indices of data["heatmap_x_nt_pos"]

    :param parsed_mutations: A dictionary containing multiple merged
        ``get_parsed_gvf_dir`` return "mutations" values.
    :type parsed_mutations: dict
    :param max_mutations_per_pos_dict: See
        ``get_max_mutations_per_pos`` return value.
    :type max_mutations_per_pos_dict: dict
    :return: List of x coordinate values to display insertion markers
    :rtype: list[int]
    """
    ret = []
    for strain in parsed_mutations:
        # How far markers need to be pushed right due to earlier
        # heterozygous mutations.
        x_offset = 0

        for i, pos in enumerate(max_mutations_per_pos_dict):
            num_of_mutations = max_mutations_per_pos_dict[pos]
            if pos in parsed_mutations[strain]:
                for j, mutation in enumerate(parsed_mutations[strain][pos]):
                    deletion = mutation["mutation_type"] == "deletion"
                    hidden = mutation["hidden_cell"]
                    if deletion and not hidden:
                        ret.append(i+j+x_offset)
            x_offset += num_of_mutations - 1
    return ret