code: def _str(self, i, x):
          
          FMT = {
              'a':self._fmt_auto,
              'i':self._fmt_int,
              'f':self._fmt_float,
              'e':self._fmt_exp,
              't':self._fmt_text,
              }
  
          n = self._precision
          dtype = self._dtype[i]
          try:
              if callable(dtype):
                  return dtype(x)
              else:
                  return FMT[dtype](x, n=n)
          except FallbackToText:
              return self._fmt_text(x)
docs: Handles string formatting of cell data
  
              i - index of the cell datatype in self._dtype
              x - cell data to format