Brackes in model variable names lead to syntax errors in ClickHouse

Variables like the one below lead to syntax errors.
```python
with pm.Model():
    pm.Uniform('b[1]', lower=1.5, upper=2.5)
```

```
clickhouse_driver.errors.ServerException: Code: 62.
DB::Exception: Syntax error: failed at position 46 ('['): [1]_interval__, b[1]_interva. Expected one of: token, Dot, UUID, Comma, ClosingRoundBracket.
```