Calculate availability in a period of time in Databricks with python and sql

Using a database where have the time when ocurrs the errors in service calculate availability using the formula:
Availability: MTBF /(MTBF+MTTR)
MTBF = Uptime / Number of System Failures
MTTR = CM Downtime / Number of System Failures

- The time is saved as string
- Is necessary send 2 parameters (start time, end time, orquest, metod)
- orquest is the service type
- metod is relative to orquest
the result of function or procedure will be availability in that period