docstr: Validate whether the sample is legal
  
  :return: bool
code: def is_legal(self):
      r"""
      Validate whether the sample is legal
  
      :return: bool
  
      """
      if self.y.field_value not in [
          "entailment",
          "neutral",
          "contradiction",
          "non-entailment",
      ]:
          return False
      return True
  
file_path: textflint/textflint/input/component/sample/nli_sample.py
imports: from .sample import Sample
  from ..field import Field, TextField
label_desc: Use image node_id 6 for calling the NLISample obj's underlying member method code with example usage: obj.is_legal() and returns: True, False