# T201

> unknown named argument

**Severity** Error

A call passes a named argument that the function does not have. Named arguments must use the exact parameter name from the signature.

Correct the name (the message lists the parameters that exist), or pass the value positionally.

## Failing example

```flowscope
script "Thick SMA"
data chart = subscribe(data.ohlcv)
plot sma = plot.line(title: "SMA 200", thickness: 2)
on chart.close {
  sma.plot(ta.sma(chart.close, 200))
}
```

## Fixed example

```flowscope
script "Thick SMA"
data chart = subscribe(data.ohlcv)
plot sma = plot.line(title: "SMA 200", width: 2)
on chart.close {
  sma.plot(ta.sma(chart.close, 200))
}
```

## Related

- [T203](/docs/scripting/reference/diagnostics/t203)
- [T215](/docs/scripting/reference/diagnostics/t215)