code: def _convert_expr(self, lj, expr):
      try:
          # Match CSE return data structure.
          if len(expr) == 2:
              tmp_exprs = expr[0]
              final_exprs = expr[1]
              if (
                  len(final_exprs) != 1
                  and self.signature.ret_type == ctypes.c_double
              ):
                  raise NotImplementedError(
                      "Return of multiple expressions not supported for this callback"
                  )
              for name, e in tmp_exprs:
                  val = lj._print(e)
                  lj._add_tmp_var(name, val)
      except TypeError:
          final_exprs = [expr]
  
      vals = [lj._print(e) for e in final_exprs]
  
      return vals
  
imports: import ctypes
  from sympy.external import import_module
  from sympy.printing.printer import Printer
  from sympy.core.singleton import S
  from sympy.tensor.indexed import IndexedBase
  from sympy.utilities.decorator import doctest_depends_on
label_desc: Use image node_id 8 for calling the LLVMJitCode obj's underlying member method code with example usage: obj._convert_expr(lj, expr) and returns: vals