code: def reify_arrays(arrays, dims, copy=True):
      
      arrays = ({ k : AttrDict(**a) for k, a in arrays.iteritems() }
          if copy else arrays)
  
      for n, a in arrays.iteritems():
          a.shape = tuple(dims[v].extent_size if isinstance(v, str) else v
              for v in a.shape)
  
      return arrays
docs: Reify arrays, given the supplied dimensions. If copy is True,
      returns a copy of arrays else performs this inplace.