code: def find_top_level_complex(gpr):
      
      logger.debug("%r", gpr)
      conform = logical_and.sub("and", gpr)
      conform = logical_or.sub("or", conform)
      conform = escape_chars.sub("_", conform)
      expression = ast.parse(conform)
      walker = GPRVisitor()
      walker.visit(expression)
      return len(walker.left ^ walker.right)
docs: Find unique elements of both branches of the top level logical AND.
  
      Parameters
      ----------
      gpr : str
          The gene-protein-reaction association as a string.
  
      Returns
      -------
      int
          The size of the symmetric difference between the set of elements to
          the left of the top level logical AND and the right set.