code: def get_quick_depths(data, sample):
      
  
      ## use existing sample cluster path if it exists, since this
      ## func can be used in step 4 and that can occur after merging
      ## assemblies after step3, and if we then referenced by data.dirs.clusts
      ## the path would be broken.
      ##
      ## If branching at step 3 to test different clust thresholds, the
      ## branched samples will retain the samples.files.clusters of the
      ## parent (which have the clust_threshold value of the parent), so
      ## it will look like nothing has changed. If we call this func
      ## from step 3 then it indicates we are in a branch and should
      ## reset the sample.files.clusters handle to point to the correct
      ## data.dirs.clusts directory. See issue #229.
      ## Easier to just always trust that samples.files.clusters is right,
      ## no matter what step?
      #if sample.files.clusters and not sample.stats.state == 3:
      #    pass
      #else:
      #    ## set cluster file handles
      sample.files.clusters = os.path.join(
           data.dirs.clusts, sample.name+".clustS.gz")
  
      ## get new clustered loci
      fclust = data.samples[sample.name].files.clusters
      clusters = gzip.open(fclust, 'r')
      pairdealer = itertools.izip(*[iter(clusters)]*2)
  
      ## storage
      depths = []
      maxlen = []
  
      ## start with cluster 0
      tdepth = 0
      tlen = 0
  
      ## iterate until empty
      while 1:
          ## grab next
          try:
              name, seq = pairdealer.next()
          except StopIteration:
              break
  
          ## if not the end of a cluster
          #print name.strip(), seq.strip()
          if name.strip() == seq.strip():
              depths.append(tdepth)
              maxlen.append(tlen)
              tlen = 0
              tdepth = 0
  
          else:
              tdepth += int(name.split(";")[-2][5:])
              tlen = len(seq)
  
      ## return
      clusters.close()
      return np.array(maxlen), np.array(depths)
docs: iterate over clustS files to get data