def subset_spectrum(spectrum,sub_spectrum):
   """Checks whether a sub spectrum is subset from a spectrum or not.
    INPUT :
        spectrum: array-like. The spectrum of the RHS.
        sub_spectrum: array-like. The spectrum of the LHS.
    OUTPUT:
        .: bool. Is sub_spectrum subset from spectrum.
   """    
   for weight in sub_spectrum:
       if weight not in spectrum:
           return False
   return True