parameters: (self, _name, _value)
docstring: Replace a header.
  
          Replace the first matching header found in the message, retaining
          header order and case.  If no matching header was found, a KeyError is
          raised.
docstring_summary: Replace a header.
docstring_tokens: Replace a header .
function: def replace_header(self, _name, _value):
          """Replace a header.
  
          Replace the first matching header found in the message, retaining
          header order and case.  If no matching header was found, a KeyError is
          raised.
          """
          _name = _name.lower()
          for i, (k, v) in zip(range(len(self._headers)), self._headers):
              if k.lower() == _name:
                  self._headers[i] = (k, _value)
                  break
          else:
              raise KeyError(_name)
function_tokens: def replace_header ( self , _name , _value ) : _name = _name . lower ( ) for i , ( k , v ) in zip ( range ( len ( self . _headers ) ) , self . _headers ) : if k . lower ( ) == _name : self . _headers [ i ] = ( k , _value ) break else : raise KeyError ( _name )