write function fails at writer._frames[0]

[mjhmilla]

The write function fails when calling 'self._frames[0] complaining that Writer has no attribute frame. Here are some details

Minimal example of the problem:

`import numpy as np
import c3d

inputFileName = 'P02_FL_Con_2FP_noGapFill.c3d'

reader = c3d.Reader(open(inputFileName, 'rb'))
writer = c3d.Writer( reader.point_rate,
reader.analog_rate,
reader.point_scale,
'mm',
1.0)

writer.add_frames(reader.read_frames())

with open('output.c3d','wb') as h:
writer.write(h,reader.point_labels)
h.close()`

Traceback (most recent call last):
File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
main, mod_spec)
File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/home/mjhmilla/.vscode/extensions/ms-python.python-2021.5.842923320/pythonFiles/lib/python/debugpy/main.py", line 45, in
cli.main()
File "/home/mjhmilla/.vscode/extensions/ms-python.python-2021.5.842923320/pythonFiles/lib/python/debugpy/../debugpy/server/cli.py", line 444, in main
run()
File "/home/mjhmilla/.vscode/extensions/ms-python.python-2021.5.842923320/pythonFiles/lib/python/debugpy/../debugpy/server/cli.py", line 285, in run_file
runpy.run_path(target_as_str, run_name=compat.force_str("main"))
File "/usr/lib/python3.6/runpy.py", line 263, in run_path
pkg_name=pkg_name, script_name=fname)
File "/usr/lib/python3.6/runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/data/projects/AutomatedMocapGapFill/Gap_Fill_Python_code/minimalWorkingExample.py", line 15, in
points,analog=writer._frame[0]
AttributeError: 'Writer' object has no attribute '_frame'

[AKuederle]

Could you please check if the issue still occures with the current version?

[AKuederle]

As #43 is merged now, I assume this is fixed. If not please repopen.