parameters: (self, attr)
return_statement: return self._doc.has_key(attr)
docstring: Returns true if the document has the attribute, false otherwise.
  
          @param attr: the attribute to check for
          @type attr: string 
          @return: True if the attribute exists, False otherwise
docstring_summary: Returns true if the document has the attribute, false otherwise.
docstring_tokens: Returns true if the document has the attribute false otherwise .
function: def has(self, attr):
          """Returns true if the document has the attribute, false otherwise.
  
          @param attr: the attribute to check for
          @type attr: string 
          @return: True if the attribute exists, False otherwise
          """
          
          return self._doc.has_key(attr)
function_tokens: def has ( self , attr ) : return self . _doc . has_key ( attr )