code: def join(self, other, how='left', lsuffix='', rsuffix=''):
          
          from pandas.core.reshape.concat import concat
  
          if isinstance(other, Panel):
              join_major, join_minor = self._get_join_index(other, how)
              this = self.reindex(major=join_major, minor=join_minor)
              other = other.reindex(major=join_major, minor=join_minor)
              merged_data = this._data.merge(other._data, lsuffix, rsuffix)
              return self._constructor(merged_data)
          else:
              if lsuffix or rsuffix:
                  raise ValueError('Suffixes not supported when passing '
                                   'multiple panels')
  
              if how == 'left':
                  how = 'outer'
                  join_axes = [self.major_axis, self.minor_axis]
              elif how == 'right':
                  raise ValueError('Right join not supported with multiple '
                                   'panels')
              else:
                  join_axes = None
  
              return concat([self] + list(other), axis=0, join=how,
                            join_axes=join_axes, verify_integrity=True)
docs: Join items with other Panel either on major and minor axes column.
  
          Parameters
          ----------
          other : Panel or list of Panels
              Index should be similar to one of the columns in this one
          how : {'left', 'right', 'outer', 'inner'}
              How to handle indexes of the two objects. Default: 'left'
              for joining on index, None otherwise
              * left: use calling frame's index
              * right: use input frame's index
              * outer: form union of indexes
              * inner: use intersection of indexes
          lsuffix : string
              Suffix to use from left frame's overlapping columns
          rsuffix : string
              Suffix to use from right frame's overlapping columns
  
          Returns
          -------
          joined : Panel