def convert_ext_to_mime(extension):
table = {<EOL>'<STR_LIT>': '<STR_LIT>',<EOL>'<STR_LIT>': '<STR_LIT>',<EOL>'<STR_LIT>': '<STR_LIT>',<EOL>'<STR_LIT>': '<STR_LIT>',<EOL>'<STR_LIT>': '<STR_LIT>',<EOL>}<EOL>if extension in table:<EOL><INDENT>return table[extension]<EOL><DEDENT>raise ValueError("<STR_LIT>")<EOL>
将扩展名转换为 MIME 格式
    :return: mime string