code: def taint_with(arg, taint, value_bits=256, index_bits=256):
      
      from ..core.smtlib import BitVecConstant  # prevent circular imports
  
      tainted_fset = frozenset((taint,))
  
      if not issymbolic(arg):
          if isinstance(arg, int):
              arg = BitVecConstant(value_bits, arg)
              arg._taint = tainted_fset
          else:
              raise ValueError("type not supported")
  
      else:
          arg = copy.copy(arg)
          arg._taint |= tainted_fset
  
      return arg
docs: Helper to taint a value.
      :param arg: a value or Expression
      :param taint: a regular expression matching a taint value (eg. 'IMPORTANT.*'). If None, this function checks for any taint value.