new_contents: from oceans.sw_extras.sw_extras import (
      sigma_t,
      sigmatheta,
      N,
      cph,
      shear,
      richnumb,
      cor_beta,
      inertial_period,
      strat_period,
      visc,
      tcond,
      spice,
      psu2ppt,
      soundspeed,
      photic_depth,
      cr_depth,
      kdpar,
      zmld_so,
      zmld_boyer,
      o2sol_SP_pt_benson_krause_84,
      )
  
  from oceans.sw_extras.gamma_GP_from_SP_pt import gamma_GP_from_SP_pt
  from oceans.sw_extras.waves import Waves
  
subject: add init