new_contents: import numpy as np
  import pyspeckit
  from astropy import units as u
  from pyspeckit.spectrum.models import ammonia_constants, ammonia
  
  # Generate a synthetic spectrum based off of 3 NH3 lines
  xarr11 = pyspeckit.units.SpectroscopicAxis(np.linspace(-30, 30, 100)*u.km/u.s,
                                             velocity_convention='radio',
                                             refX=ammonia_constants.freq_dict['oneone']).as_unit(u.GHz)
  xarr22 = pyspeckit.units.SpectroscopicAxis(np.linspace(-30, 30, 100)*u.km/u.s,
                                             velocity_convention='radio',
                                             refX=ammonia_constants.freq_dict['twotwo']).as_unit(u.GHz)
  xarr33 = pyspeckit.units.SpectroscopicAxis(np.linspace(-30, 30, 100)*u.km/u.s,
                                             velocity_convention='radio',
                                             refX=ammonia_constants.freq_dict['threethree']).as_unit(u.GHz)
  xarr = pyspeckit.units.SpectroscopicAxes([xarr11,xarr22,xarr33])
  
  synthspec = (ammonia.ammonia(xarr, tkin=20, ntot=15, fortho=0.5) +
               ammonia.ammonia(xarr, tkin=50, ntot=14, fortho=0.5))
  
  spectrum = pyspeckit.Spectrum(xarr=xarr, data=synthspec)
  
  spectrum.plotter()
  
subject: add a new ammonia example