Ground state generation fails if for certain concentrations

 Traceback (most recent call last):
   File "/home/gudrun/davidkl/Documents/clease/clease/gui/newStructPage.py", line 105, in generate
     num_steps_per_temp=self.num_steps, eci=self.eci)
   File "/home/gudrun/davidkl/Documents/clease/clease/newStruct.py", line 215, in generate_gs_structure_multiple_templates
     eci=eci
   File "/home/gudrun/davidkl/Documents/clease/clease/newStruct.py", line 271, in _generate_one_gs_structure_multiple_templates
     gs_struct, _ = es.generate()
   File "/home/gudrun/davidkl/Documents/clease/clease/structure_generator.py", line 461, in generate
     mc.run(steps=self.num_steps_per_temp)
   File "/home/gudrun/davidkl/Documents/clease/clease/montecarlo/montecarlo.py", line 346, in run
     self._check_symbols()
   File "/home/gudrun/davidkl/Documents/clease/clease/montecarlo/montecarlo.py", line 244, in _check_symbols
     "There is only one element in the given atoms object!")
 clease.montecarlo.montecarlo.TooFewElementsError: There is only one element in the given atoms object

This happens produces an initial concentration with two or less elements in a basis