code: def get_parents(docgraph, child_node, strict=True):
      
      parents = []
      for src, _, edge_attrs in docgraph.in_edges(child_node, data=True):
          if edge_attrs['edge_type'] == EdgeTypes.dominance_relation:
              parents.append(src)
  
      if strict and len(parents) > 1:
          raise ValueError(("In a syntax tree, a node can't be "
                            "dominated by more than one parent"))
      return parents
docs: Return a list of parent nodes that dominate this child.
  
      In a 'syntax tree' a node never has more than one parent node
      dominating it. To enforce this, set strict=True.
  
      Parameters
      ----------
      docgraph : DiscourseDocumentGraph
          a document graph
      strict : bool
          If True, raise a ValueError if a child node is dominated
          by more than one parent node.
  
      Returns
      -------
      parents : list
          a list of (parent) node IDs.