def get_mean_cov(start, end, coverage, bin_size):
    """
    Extract mean (average) coverage of a given region.
    Args:
       start (int): start location of region (ex: 250)
       end (int): end location of region (ex: 400)
       coverage (str): coverage list name
       bin_size (int): bin size used for bedgraph generation
    Returns:
       mean_cov (int): mean coverage value
    """
    interval_values = coverage[int(start/bin_size):int(end/bin_size)+1]
    return sum(interval_values)/len(interval_values)