code: def _convert_to_side(cls, side_spec):
          
  
          from openpyxl.styles import Side
  
          _side_key_map = {
              'border_style': 'style',
          }
  
          if isinstance(side_spec, str):
              return Side(style=side_spec)
  
          side_kwargs = {}
          for k, v in side_spec.items():
              if k in _side_key_map:
                  k = _side_key_map[k]
              if k == 'color':
                  v = cls._convert_to_color(v)
              side_kwargs[k] = v
  
          return Side(**side_kwargs)
docs: Convert ``side_spec`` to an openpyxl v2 Side object
          Parameters
          ----------
          side_spec : str, dict
              A string specifying the border style, or a dict with zero or more
              of the following keys (or their synonyms).
                  'style' ('border_style')
                  'color'
          Returns
          -------
          side : openpyxl.styles.Side