code: def assignrepr(self, prefix, style=None, utcoffset=None):
          
          skip = len(prefix) + 9
          blanks = ' ' * skip
          return (f"{prefix}Timegrid('"
                  f"{self.firstdate.to_string(style, utcoffset)}',\n"
                  f"{blanks}'{self.lastdate.to_string(style, utcoffset)}',\n"
                  f"{blanks}'{str(self.stepsize)}')")
docs: Return a |repr| string with an prefixed assignement.
  
          Without option arguments given, printing the returned string
          looks like:
  
          >>> from hydpy import Timegrid
          >>> timegrid = Timegrid('1996-11-01 00:00:00',
          ...                     '1997-11-01 00:00:00',
          ...                     '1d')
          >>> print(timegrid.assignrepr(prefix='timegrid = '))
          timegrid = Timegrid('1996-11-01 00:00:00',
                              '1997-11-01 00:00:00',
                              '1d')
  
          The optional arguments are passed to method |Date.to_repr|
          without any modifications:
  
          >>> print(timegrid.assignrepr(
          ...     prefix='', style='iso1', utcoffset=120))
          Timegrid('1996-11-01T01:00:00+02:00',
                   '1997-11-01T01:00:00+02:00',
                   '1d')