old_contents: from galpy.df_src import diskdf
  from galpy.df_src import surfaceSigmaProfile
  from galpy.df_src import evolveddiskdf
  from galpy.df_src import quasiisothermaldf
  from galpy.df_src import streamdf
  from galpy.df_src import streamgapdf
  #
  # Functions
  #
  impulse_deltav_plummer= streamgapdf.impulse_deltav_plummer
  impulse_deltav_plummer_curvedstream= streamgapdf.impulse_deltav_plummer_curvedstream
  impulse_deltav_hernquist= streamgapdf.impulse_deltav_hernquist
  impulse_deltav_hernquist_curvedstream= streamgapdf.impulse_deltav_hernquist_curvedstream
  impulse_deltav_general= streamgapdf.impulse_deltav_general
  impulse_deltav_general_curvedstream= streamgapdf.impulse_deltav_general_curvedstream
  impulse_deltav_general_orbitintegration= streamgapdf.impulse_deltav_general_orbitintegration
  impulse_deltav_general_fullplummerintegration= streamgapdf.impulse_deltav_general_fullplummerintegration
  #
  # Classes
  #
  shudf= diskdf.shudf
  dehnendf= diskdf.dehnendf
  DFcorrection= diskdf.DFcorrection
  diskdf= diskdf.diskdf
  evolveddiskdf= evolveddiskdf.evolveddiskdf
  expSurfaceSigmaProfile= surfaceSigmaProfile.expSurfaceSigmaProfile
  surfaceSigmaProfile= surfaceSigmaProfile.surfaceSigmaProfile
  quasiisothermaldf= quasiisothermaldf.quasiisothermaldf
  streamdf= streamdf.streamdf
  streamgapdf= streamgapdf.streamgapdf
  
new_contents: from galpy.df_src import diskdf
  from galpy.df_src import surfaceSigmaProfile
  from galpy.df_src import evolveddiskdf
  from galpy.df_src import quasiisothermaldf
  from galpy.df_src import streamdf
  from galpy.df_src import streamgapdf
  #
  # Functions
  #
  impulse_deltav_plummer= streamgapdf.impulse_deltav_plummer
  impulse_deltav_plummer_curvedstream= streamgapdf.impulse_deltav_plummer_curvedstream
  impulse_deltav_hernquist= streamgapdf.impulse_deltav_hernquist
  impulse_deltav_hernquist_curvedstream= streamgapdf.impulse_deltav_hernquist_curvedstream
  impulse_deltav_general= streamgapdf.impulse_deltav_general
  impulse_deltav_general_curvedstream= streamgapdf.impulse_deltav_general_curvedstream
  impulse_deltav_general_orbitintegration= streamgapdf.impulse_deltav_general_orbitintegration
  impulse_deltav_general_fullplummerintegration= streamgapdf.impulse_deltav_general_fullplummerintegration
  impulse_deltav_plummerstream= streamgapdf.impulse_deltav_plummerstream
  impulse_deltav_plummerstream_curvedstream= streamgapdf.impulse_deltav_plummerstream_curvedstream
  #
  # Classes
  #
  shudf= diskdf.shudf
  dehnendf= diskdf.dehnendf
  DFcorrection= diskdf.DFcorrection
  diskdf= diskdf.diskdf
  evolveddiskdf= evolveddiskdf.evolveddiskdf
  expSurfaceSigmaProfile= surfaceSigmaProfile.expSurfaceSigmaProfile
  surfaceSigmaProfile= surfaceSigmaProfile.surfaceSigmaProfile
  quasiisothermaldf= quasiisothermaldf.quasiisothermaldf
  streamdf= streamdf.streamdf
  streamgapdf= streamgapdf.streamgapdf
  
subject: Add new impulses to top level