I hope to parse a '.xml' file using python. The format of the file is as follows:

```
<root><dm_log_packet>
    <pair key ="type_id">LTE_PHY_Serv_Cell_Measurement</pair>
  </dm_log_packet>
</root>

```

I tried to parse it using ElementTree but failed.

Here is my code:

```py
from xml.etree import ElementTree

class Log:
    def __init__(self,type_id=None):
        self.type_id=type_id
    def __str__(self):
        return self.type_id

roota=ElementTree.parse("file.xml")
log_file = roota.findall("dm_log_packet")

lo = []
for aa in log_file:
    log = Log()
    log.type_id = aa.find("type_id").text
    lo.append(log)

```

I expect to parse each pair, but it can't do it like I have a `<type_id>...</type_id>` pair.