code: def return_values_ssa(self):
          
          from slither.core.cfg.node import NodeType
          from slither.slithir.operations import Return
          from slither.slithir.variables import Constant
  
          if self._return_values_ssa is None:
              return_values_ssa = list()
              returns = [n for n in self.nodes if n.type == NodeType.RETURN]
              [return_values_ssa.extend(ir.values) for node in returns for ir in node.irs_ssa if isinstance(ir, Return)]
              self._return_values_ssa = list(set([x for x in return_values_ssa if not isinstance(x, Constant)]))
          return self._return_values_ssa
docs: list(Return Values in SSA form): List of the return values in ssa form