def get_value(self, item, source_name):
val = item.get(source_name.encode('<STR_LIT:utf-8>'), None)<EOL>if val is not None:<EOL><INDENT>val = convert_string(val)<EOL><DEDENT>return val<EOL>
This method receives an item from the source and a source name,
and returns the text content for the `source_name` node.