old_contents: from beam_construct import beam
  
  class BeamFile(object):
  	def __init__(self, filename):
  		self._tree = beam.parse(file(filename,"r").read())
  
  	
  
new_contents: from beam_construct import beam
  
  class BeamFile(object):
  	def __init__(self, filename):
  		self._tree = beam.parse(file(filename,"r").read())
  
  	def selectChunkByName(self, name):
  		for c in self._tree.chunk:
  			if c.chunk_name == name:
  				return c
  		raise KeyError(name)
  
  	@property
  	def atoms(self):
  		return self.selectChunkByName("Atom").payload.atom
  
subject: Add @property atoms