code: def unique(self, e, **kwargs):
          
          if not isinstance(e, claripy.ast.Base):
              return True
  
          # if we don't want to do symbolic checks, assume symbolic variables are multivalued
          if o.SYMBOLIC not in self.state.options and self.symbolic(e):
              return False
  
          r = self.eval_upto(e, 2, **kwargs)
          if len(r) == 1:
              self.add(e == r[0])
              return True
          elif len(r) == 0:
              raise SimValueError("unsatness during uniqueness check(ness)")
          else:
              return False
docs: Returns True if the expression `e` has only one solution by querying
          the constraint solver. It does also add that unique solution to the
          solver's constraints.