class_docstr: Generates a motif based on a custom structure coming from a
  :class:`torch_geometric.data.Data` or :class:`networkx.Graph` object.
  
  Args:
      structure (torch_geometric.data.Data or networkx.Graph): The structure
          to use as a motif.
code: def __init__(self, structure: Any):
      super().__init__()
  
      self.structure: Optional[Data] = None
  
      if isinstance(structure, Data):
          self.structure = structure
      else:
          try:
              import networkx as nx
  
              if isinstance(structure, nx.Graph):
                  self.structure = from_networkx(structure)
          except ImportError:
              pass
  
      if self.structure is None:
          raise ValueError(
              f"Expected a motif structure of type "
              f"'torch_geometric.data.Data' or 'networkx.Graph'"
              f"(got {type(structure)})"
          )
  
imports: from typing import Any, Optional
  from torch_geometric.data import Data
  from torch_geometric.datasets.motif_generator import MotifGenerator
  from torch_geometric.utils import from_networkx
label_desc: Use image node_id 1 to create a new CustomMotif object from inherited base classes: MotifGenerator with example: obj = CustomMotif(structure)