\`switch.py\` line 137 concatenates the operator directly after the text
without separator:
\`'Not supported operator' + operator\` → produces \`"Not supported
operatorXXX"\`
Changed to: \`f'Not supported operator: {operator}'\`
### What problem does this PR solve?
Add mechanism to check cancellation in Agent.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
issue：#5617
change：add IBM DB2 support in ExeSQL
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
#9082#6365
<u> **WARNING: it's not compatible with the older version of `Agent`
module, which means that `Agent` from older versions can not work
anymore.**</u>
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
