code: def _vasprun_float(f):
      
      try:
          return float(f)
      except ValueError as e:
          f = f.strip()
          if f == '*' * len(f):
              warnings.warn('Float overflow (*******) encountered in vasprun')
              return np.nan
          raise e
docs: Large numbers are often represented as ********* in the vasprun.
      This function parses these values as np.nan