TypeError when generic or company is none

[sainak]

Sentry Issue: CARE-QY

TypeError: 'Prescription' object is not subscriptable
  File "django/template/base.py", line 880, in _resolve_lookup
    current = current[bit]

TypeError: sequence item 1: expected str instance, NoneType found
(22 additional frame(s) were not displayed)
...
  File "care/facility/tasks/discharge_report.py", line 21, in generate_and_upload_discharge_summary_task
    file_db_entry = generate_and_upload_discharge_summary(consultation_id)
  File "care/facility/utils/reports/discharge_report.py", line 106, in generate_and_upload_discharge_summary
    generate_discharge_summary_pdf(data, file)
  File "care/facility/utils/reports/discharge_report.py", line 77, in generate_discharge_summary_pdf
    html_string = render_to_string("reports/patient_pdf_report.html", data)
  File "care/facility/models/prescription.py", line 139, in medicine_name
    return str(self.medicine) if self.medicine else self.medicine_old
  File "care/facility/models/prescription.py", line 67, in __str__
    return " - ".join([self.name, self.generic, self.company])

[sentry-io]

Sentry issue: CARE-QY