code: def any_from_filename(filename, prefix_dir=None):
      
      if not isinstance(filename, basestr):
          if isinstance(filename, MeshIO):
              return filename
  
          else:
              return UserMeshIO(filename)
  
      ext = op.splitext(filename)[1].lower()
      try:
          format = supported_formats[ext]
      except KeyError:
          raise ValueError('unsupported mesh file suffix! (%s)' % ext)
  
      if isinstance(format, tuple):
          format = guess_format(filename, ext, format, io_table)
  
      if prefix_dir is not None:
          filename = op.normpath(op.join(prefix_dir, filename))
  
      return io_table[format](filename)
docs: Create a MeshIO instance according to the kind of `filename`.
  
      Parameters
      ----------
      filename : str, function or MeshIO subclass instance
          The name of the mesh file. It can be also a user-supplied function
          accepting two arguments: `mesh`, `mode`, where `mesh` is a Mesh
          instance and `mode` is one of 'read','write', or a MeshIO subclass
          instance.
      prefix_dir : str
          The directory name to prepend to `filename`.
  
      Returns
      -------
      io : MeshIO subclass instance
          The MeshIO subclass instance corresponding to the kind of `filename`.