def get_size_from_block_count(block_count_str, size_step=1000, sizes = ["K", "M", "G", "T"], format_spec=":2.2f"):
    """Transforms block count (as returned by /proc/partitions and similar files) to a human-readable size string, with size multiplier ("K", "M", "G" etc.) appended.

    Kwargs:

        * ``size_step``: size of each multiplier
        * ``sizes``: list of multipliers to be used
        *``format_spec``: value formatting specification for the final string
    """
    block_count = float(block_count_str)
    size_counter = 0
    while block_count >= float(size_step):
        block_count /= size_step
        size_counter += 1
    return ("{"+format_spec+"}{}").format(block_count, sizes[size_counter])