code: def make_energies_hdu(energy_vals, extname="ENERGIES"):
      
      cols = [fits.Column("Energy", "D", unit='MeV', array=energy_vals)]
      hdu = fits.BinTableHDU.from_columns(cols, name=extname)
      return hdu
docs: Builds and returns a FITs HDU with the energy values
  
      extname   : The HDU extension name