def get_bytes_from_blob(val) -> bytes:
if isinstance(val, bytes):<EOL><INDENT>return val<EOL><DEDENT>elif isinstance(val, memoryview):<EOL><INDENT>return val.tobytes()<EOL><DEDENT>else:<EOL><INDENT>raise TypeError('<STR_LIT>')<EOL><DEDENT>
不同数据库从blob拿出的数据有所差别，有的是memoryview有的是bytes