old_contents: """
  This contains the base class for the geometry engine, which proposes new positions
  for each additional atom that must be added.
  """
  from collections import namedtuple
  import numpy as np
  
  GeometryProposal = namedtuple('GeometryProposal',['new_positions','logp_ratio'])
  
  class GeometryEngine(object):
      """
      This is the base class for the geometry engine.
      
      Arguments
      ---------
      topology_proposal : TopologyProposal namedtuple
          The result of the topology proposal, containing the atom mapping and topologies.
      current_positions : numpy.ndarray of floats
          The positions of the old system, used for the new geometry proposal
      """
      
      def __init__(self, topology_proposal, current_positions):
           pass
  
  
      def propose(self):
          """
          Make a geometry proposal for the appropriate atoms.
          
          Returns
          -------
          proposal : GeometryProposal namedtuple
               Contains the new positions as well as the logp ratio
               of the proposal.
          """
          return GeometryProposal(np.array([0.0,0.0,0.0]), 0)
  
  
                    
  
new_contents: """
  This contains the base class for the geometry engine, which proposes new positions
  for each additional atom that must be added.
  """
  from collections import namedtuple
  import numpy as np
  
  GeometryProposal = namedtuple('GeometryProposal',['new_positions','logp'])
  
  class GeometryEngine(object):
      """
      This is the base class for the geometry engine.
      
      Arguments
      ---------
      topology_proposal : TopologyProposal namedtuple
          The result of the topology proposal, containing the atom mapping and topologies.
      current_positions : numpy.ndarray of floats
          The positions of the old system, used for the new geometry proposal
      """
      
      def __init__(self, topology_proposal, current_positions):
           pass
  
  
      def propose(self):
          """
          Make a geometry proposal for the appropriate atoms.
          
          Returns
          -------
          proposal : GeometryProposal namedtuple
               Contains the new positions as well as the logp ratio
               of the proposal.
          """
          return GeometryProposal(np.array([0.0,0.0,0.0]), 0)
  
  
                    
  
subject: change geometryproposal namedtuple logp name