class_docstr: Policy Object basic framework.
  
  This class is useless unless subclassed.  A subclass should define
  class attributes with defaults for any values that are to be
  managed by the Policy object.  The constructor will then allow
  non-default values to be set for these attributes at instance
  creation time.  The instance will be callable, taking these same
  attributes keyword arguments, and returning a new instance
  identical to the called instance except for those values changed
  by the keyword arguments.  Instances may be added, yielding new
  instances with any non-default values from the right hand
  operand overriding those in the left hand operand.  That is,
  
      A + B == A(<non-default values of B>)
  
  The repr of an instance can be used to reconstruct the object
  if and only if the repr of the values can be used to reconstruct
  those values.
docstr: Create new Policy, possibly overriding some defaults.
  
  See class docstring for a list of overridable attributes.
docstr_tok: ["Create","new","Policy",",","possibly","overriding","some","defaults",".","See","class","docstring","for","a","list","of","overridable","attributes","."]
code: def __init__(self, **kw):
      """Create new Policy, possibly overriding some defaults.
  
      See class docstring for a list of overridable attributes.
  
      """
      for name, value in kw.items():
          if hasattr(self, name):
              super(_PolicyBase, self).__setattr__(name, value)
          else:
              raise TypeError(
                  "{!r} is an invalid keyword argument for {}".format(
                      name, self.__class__.__name__
                  )
              )
  
imports: import abc
  from email import header
  from email import charset
  from email.utils import _has_surrogates
label_desc: Use image node_id 1 to create a new _PolicyBase object  with example: obj = _PolicyBase()