code: def _is_compound_mass_tuple(self, value):
          
  
          if not type(value) is tuple:
              return False
          elif not len(value) == 2:
              return False
          elif not type(value[0]) is str:
              return False
          elif not type(value[1]) is float and \
                  not type(value[1]) is numpy.float64 and \
                  not type(value[1]) is numpy.float32:
              return False
          else:
              return True
docs: Determines whether value is a tuple of the format
          (compound(str), mass(float)).
  
          :param value: The value to be tested.
  
          :returns: True or False