def pseudomedian(self,chrom=''):
        """Return the pseudo median. Here Pseudo median means the median of medians of chromosomes. 
        
        Parameters:
        1. chrom: if '', return the max of the whole wig; otherwise, return the maxi of the chrom
        
        Note that this method is under construction. The method using sorting might take a long time and a large amount of memory.
        """
        
        if chrom:
            meds = []
            for chr in self.get_chroms():
                meds.append(median(self[chrom][1]))
            return median(meds)
        else:
            try:
                return median(self[chrom][1])
            except __HOLE__:
                return None
dataset/ETHPy150Open taoliu/taolib/Assoc/inout.py/Wig.pseudomedian