def add_metadata(file_name, title, artist, album):
tags = EasyMP3(file_name)<EOL>if title: <EOL><INDENT>tags["<STR_LIT:title>"] = title<EOL><DEDENT>if artist:     <EOL><INDENT>tags["<STR_LIT>"] = artist<EOL><DEDENT>if album:<EOL><INDENT>tags["<STR_LIT>"] = album<EOL><DEDENT>tags.save()<EOL>return file_name<EOL>
As the method name suggests