old_contents: from __future__ import absolute_import, division, print_function
  
  from .core import pre_compute
  from ..expr import Expr, Field
  from ..dispatch import dispatch
  from odo import into, chunks
  import pandas as pd
  
  @dispatch(Expr, pd.io.pytables.AppendableFrameTable)
  def pre_compute(expr, data, **kwargs):
      return into(chunks(pd.DataFrame), data, **kwargs)
  
  
  @dispatch(Expr, pd.io.pytables.Fixed)
  def pre_compute(expr, data, **kwargs):
      return into(pd.DataFrame, data, **kwargs)
  
  
  @dispatch(Field, pd.HDFStore)
  def compute_up(expr, data, **kwargs):
      key = '/' + expr._name
      if key in data.keys():
          return data.get_storer(key)
      else:
          return HDFGroup(data, key)
  
  
  from collections import namedtuple
  HDFGroup = namedtuple('HDFGroup', 'parent,datapath')
  
  
  @dispatch(Field, HDFGroup)
  def compute_up(expr, data, **kwargs):
      key = data.datapath + '/' + expr._name
      if key in data.parent.keys():
          return data.parent.get_storer(key)
      else:
          return HDFGroup(data.parent, key)
  
new_contents: from __future__ import absolute_import, division, print_function
  
  from collections import namedtuple
  
  from .core import pre_compute
  from ..expr import Expr, Field
  from ..dispatch import dispatch
  
  from odo import into, chunks
  
  import pandas as pd
  
  
  @dispatch(Expr, pd.io.pytables.AppendableFrameTable)
  def pre_compute(expr, data, **kwargs):
      return into(chunks(pd.DataFrame), data, **kwargs)
  
  
  @dispatch(Expr, pd.io.pytables.Fixed)
  def pre_compute(expr, data, **kwargs):
      return into(pd.DataFrame, data, **kwargs)
  
  
  @dispatch(Field, pd.HDFStore)
  def compute_up(expr, data, **kwargs):
      key = '/' + expr._name
      if key in data.keys():
          return data.get_storer(key)
      else:
          return HDFGroup(data, key)
  
  
  HDFGroup = namedtuple('HDFGroup', 'parent,datapath')
  
  
  @dispatch(Field, HDFGroup)
  def compute_up(expr, data, **kwargs):
      key = data.datapath + '/' + expr._name
      if key in data.parent.keys():
          return data.parent.get_storer(key)
      else:
          return HDFGroup(data.parent, key)
  
subject: Move namedtuple to the top of the file