parameters: (self, varname)
return_statement: return (varname in self.locals_ptr)
docstring: ``exists()`` for the sandboxed code.
          
          Test if the variable `varname` exists in the current locals-namespace.
  
          This only works for single variable names. If you want to test
          complicated expressions, use i.e. `default`.
          (i.e. `default("expr",False)`)
  
          :Note:      the variable-name has to be quoted! (like in eval)
          :Example:   see module-docstring
docstring_summary: ``exists()`` for the sandboxed code.
          
          Test if the variable `varname` exists in the current locals-namespace.
docstring_tokens: exists () for the sandboxed code . Test if the variable varname exists in the current locals - namespace .
function: def f_exists(self, varname):
          """``exists()`` for the sandboxed code.
          
          Test if the variable `varname` exists in the current locals-namespace.
  
          This only works for single variable names. If you want to test
          complicated expressions, use i.e. `default`.
          (i.e. `default("expr",False)`)
  
          :Note:      the variable-name has to be quoted! (like in eval)
          :Example:   see module-docstring
          """
          return (varname in self.locals_ptr)
function_tokens: def f_exists ( self , varname ) : return ( varname in self . locals_ptr )