parameters: (self, name)
return_statement: return self.get(name, missing) is not missing
docstring: Return true if the message contains the header.
docstring_summary: Return true if the message contains the header.
docstring_tokens: Return true if the message contains the header .
function: def has_key(self, name):
          """Return true if the message contains the header."""
          missing = object()
          return self.get(name, missing) is not missing
function_tokens: def has_key ( self , name ) : missing = object ( ) return self . get ( name , missing ) is not missing