Missing "Result" Attribute makes Live Opta parsing impossible

Hi!

A really simple fix here. When loading opta event data (as shown below) for an incomplete f7 (read: during live matches) we get an AttributeError.

dataset = opta.load(
    f7_data="f7.xml",
    f24_data="f24.xml"
)

Error looks as follows:

Traceback (most recent call last):
  File "/workspaces/kloppy/_dev.py", line 3, in <module>
    dataset = opta.load(
  File "/workspaces/kloppy/kloppy/_providers/opta.py", line 35, in load
    return deserializer.deserialize(
  File "/workspaces/kloppy/kloppy/infra/serializers/event/opta/deserializer.py", line 729, in deserialize
    match_result_type = list(match_result_path.find(f7_root))[
  File "src/lxml/objectpath.pxi", line 55, in lxml.objectify.ObjectPath.__call__
  File "src/lxml/objectpath.pxi", line 219, in lxml.objectify._find_object_path
AttributeError: no such child: Result

Normally, in a completed game we'd have a Result tag that looks something like this:

<Result Type="Aggregate" Winner="t12345" />

But, because the game is not finished yet there simply is no "Result" tag.

Doing a simple try / except block like below resolves this issue and creates a correct Kloppy EventDataset.

try:
              match_result_type = list(match_result_path.find(f7_root))[
                  0
              ].attrib["Type"]
          except AttributeError:
              match_result_type = None

Not 100% sure if using a try-except block here is the best solution, but it works.

PySport / kloppy

Missing "Result" Attribute makes Live Opta parsing impossible #321