code: def sparkify(series):
      u
      series = [ float(i) for i in series ]
      minimum = min(series)
      maximum = max(series)
      data_range = maximum - minimum
      if data_range == 0.0:
          # Graph a baseline if every input value is equal.
          return u''.join([ spark_chars[0] for i in series ])
      coefficient = (len(spark_chars) - 1.0) / data_range
      return u''.join([
          spark_chars[
              int(round((x - minimum) * coefficient))
          ] for x in series
      ])
docs: u"""Converts <series> to a sparkline string.
      
      Example:
      >>> sparkify([ 0.5, 1.2, 3.5, 7.3, 8.0, 12.5, 13.2, 15.0, 14.2, 11.8, 6.1,
      ... 1.9 ])
      u'▁▁▂▄▅▇▇██▆▄▂'
  
      >>> sparkify([1, 1, -2, 3, -5, 8, -13])
      u'▆▆▅▆▄█▁'
  
      Raises ValueError if input data cannot be converted to float.
      Raises TypeError if series is not an iterable.