Conversion of normalised data to JSON failure

[madwort]

this error was received by email:

Traceback (most recent call last):
  File "./manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/var/www/eutrialstracker_live/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/var/www/eutrialstracker_live/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/var/www/eutrialstracker_live/venv/lib/python3.6/site-packages/django/core/management/base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/var/www/eutrialstracker_live/venv/lib/python3.6/site-packages/django/core/management/base.py", line 364, in execute
    output = self.handle(*args, **options)
  File "/var/www/eutrialstracker_live/euctr-tracker-code/euctr/euctr/management/commands/update_trials_json.py", line 403, in handle
    all_sponsors = make_sponsors_json(trials_and_sponsors)
  File "/var/www/eutrialstracker_live/euctr-tracker-code/euctr/euctr/management/commands/update_trials_json.py", line 271, in make_sponsors_json
    sponsor_counts = sponsor_grouped.apply(do_counts)
  File "/var/www/eutrialstracker_live/venv/lib/python3.6/site-packages/pandas/core/groupby.py", line 694, in apply
    return self._python_apply_general(f)
  File "/var/www/eutrialstracker_live/venv/lib/python3.6/site-packages/pandas/core/groupby.py", line 698, in _python_apply_general
    self.axis)
  File "/var/www/eutrialstracker_live/venv/lib/python3.6/site-packages/pandas/core/groupby.py", line 1611, in apply
    res = f(group)
  File "/var/www/eutrialstracker_live/euctr-tracker-code/euctr/euctr/management/commands/update_trials_json.py", line 257, in do_counts
    parent_names.remove(sponsor_name)
ValueError: list.remove(x): x not in list