code: def getChromBounds(data):
      
      chrom= data.geno['col_header']['chrom'][:]
      posCum = getCumPos(data)
      n_chroms = int(chrom.max())
      chrom_bounds = []
      for chrom_i in range(2,n_chroms+1):
          I1 = chrom==chrom_i
          I0 = chrom==chrom_i-1
          _cb = 0.5*(posCum[I0].max()+posCum[I1].min())
          chrom_bounds.append(_cb)
      return chrom_bounds
docs: getChromBounds