Unexpected field-error for a boolean "example" with "trueValues" or "falseValues" properties

Overview

Using frictionless validate I got this unvalid report of validation:

frictionless validate data.csv --schema schema.json
──────────────────────────────────────────────────────────────────────────────────────────────────────────── Dataset ─────────────────────────────────────────────────────────────────────────────────────────────────────────────
               dataset               
┏━━━━━━┳━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┓
┃ name ┃ type  ┃ path     ┃ status  ┃
┡━━━━━━╇━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━┩
│ data │ table │ data.csv │ INVALID │
└──────┴───────┴──────────┴─────────┘
───────────────────────────────────────────────────────────────────────────────────────────────────────────── Tables ─────────────────────────────────────────────────────────────────────────────────────────────────────────────
                                                 data                                                  
┏━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Row  ┃ Field ┃ Type        ┃ Message                                                                ┃
┡━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ None │ None  │ field-error │ Field is not valid: example value "no" for field "IsTrue" is not valid │
└──────┴───────┴─────────────┴────────────────────────────────────────────────────────────────────────┘

The error is related to the value given in the example property of the field 'IsTrue' of type boolean in the schema used for the validation, which is not valid.

I was expected a valid report of validation: I was not expected an field-error on this value example which matches with the falseValues property value, as mentionned in the boolean type of TableSchema documentation.

Resources used to reproduce the problem

schema.json:

{
  "$schema": "https://frictionlessdata.io/schemas/table-schema.json",
  "fields": [
    {
      "name": "IsTrue",
      "type": "boolean",
      "trueValues": ["yes"],
      "falseValues": ["no"],
      "example": "no"
    }]
}

data.csv:
```
IsTrue
no
yes
```

Note

Replacing in the schema field 'IsTrue' the optionnal property example with 'false' instead of 'no' solves the problem. The validation report is now valid with this new schema:

schema.json:

{
  "$schema": "https://frictionlessdata.io/schemas/table-schema.json",
  "fields": [
    {
      "name": "IsTrue",
      "type": "boolean",
      "trueValues": ["yes"],
      "falseValues": ["no"],
      "example": "false"
    }]
}

data.csv:
```
IsTrue
no
yes
```

frictionless validate data.csv --schema schema.json
──────────────────────────────────────────────────────────────────────────────────────────────────────────── Dataset ─────────────────────────────────────────────────────────────────────────────────────────────────────────────
              dataset               
┏━━━━━━┳━━━━━━━┳━━━━━━━━━━┳━━━━━━━━┓
┃ name ┃ type  ┃ path     ┃ status ┃
┡━━━━━━╇━━━━━━━╇━━━━━━━━━━╇━━━━━━━━┩
│ data │ table │ data.csv │ VALID  │
└──────┴───────┴──────────┴────────┘

As specified in the TableSchema boolean type documentation : "The boolean field can be customised with these additional properties: trueValues: [ "true", "True", "TRUE", "1" ] falseValues: [ "false", "False", "FALSE", "0" ] format: no options (other than the default)."

But, in this case the falseValues property seems to not be applied on the example property by frictionless and retruns an unexpected field-error in the validation report.

frictionlessdata / frictionless-py