class_docstr: A plain python object modeling a single graph with various
  (optional) attributes:
  
  Args:
      x (Tensor, optional): Node feature matrix with shape :obj:`[num_nodes,
          num_node_features]`. (default: :obj:`None`)
      edge_index (LongTensor, optional): Graph connectivity in COO format
          with shape :obj:`[2, num_edges]`. (default: :obj:`None`)
      edge_attr (Tensor, optional): Edge feature matrix with shape
          :obj:`[num_edges, num_edge_features]`. (default: :obj:`None`)
      y (Tensor, optional): Graph or node targets with arbitrary shape.
          (default: :obj:`None`)
      pos (Tensor, optional): Node position matrix with shape
          :obj:`[num_nodes, num_dimensions]`. (default: :obj:`None`)
  
  The data object is not restricted to these attributes and can be extented
  by any other additional data.
docstr: Gets the data of the attribute :obj:`key`.
docstr_tok: ["Gets","the","data","of","the","attribute",":","obj",":","`","key","`","."]
code: def __getitem__(self, key):
      r"""Gets the data of the attribute :obj:`key`."""
      return getattr(self, key)
  
imports: import re
  import torch
label_desc: Use image node_id 3 for calling the Data obj's underlying member method code with example usage: obj.__getitem__(key) and returns: getattr