old_contents: from pysb.core import Observe, Initial, MatchOnce, Model, Monomer, Parameter, \
      Compartment, Rule, ANY, WILD
  
  try:
      import reinteract         # fails if reinteract not installed
      reinteract.custom_result  # fails if this code is run outside of the reinteract shell
  except (ImportError, AttributeError) as e:
      pass                      # silently skip applying the mixin below
  else:
      import pysb.reinteract_integration
      pysb.reinteract_integration.apply_mixins()
  
new_contents: from pysb.core import *
  
  __all__ = ['Observe', 'Initial', 'MatchOnce', 'Model', 'Monomer',
             'Parameter', 'Compartment', 'Rule', 'ANY', 'WILD']
  
  try:
      import reinteract         # fails if reinteract not installed
      reinteract.custom_result  # fails if this code is run outside of the reinteract shell
  except (ImportError, AttributeError) as e:
      pass                      # silently skip applying the mixin below
  else:
      import pysb.reinteract_integration
      pysb.reinteract_integration.apply_mixins()
  
subject: clean up __all__ even more