code: def preconstrain(self, value, variable):
          
          if not isinstance(value, claripy.ast.Base):
              value = self.state.solver.BVV(value, len(variable))
          elif value.op != 'BVV':
              raise ValueError("Passed a value to preconstrain that was not a BVV or a string")
  
          if variable.op not in claripy.operations.leaf_operations:
              l.warning("The variable %s to preconstrain is not a leaf AST. This may cause replacement failures in the "
                        "claripy replacement backend.", variable)
              l.warning("Please use a leaf AST as the preconstraining variable instead.")
  
          constraint = variable == value
          l.debug("Preconstraint: %s", constraint)
  
          # add the constraint for reconstraining later
          self.variable_map[next(iter(variable.variables))] = constraint
          self.preconstraints.append(constraint)
          if o.REPLACEMENT_SOLVER in self.state.options:
              self.state.solver._solver.add_replacement(variable, value, invalidate_cache=False)
          else:
              self.state.add_constraints(*self.preconstraints)
          if not self.state.satisfiable():
              l.warning("State went unsat while adding preconstraints")
docs: Add a preconstraint that ``variable == value`` to the state.
  
          :param value:       The concrete value. Can be a bitvector or a bytestring or an integer.
          :param variable:    The BVS to preconstrain.