class_docstr: Provide various chord evaluation scores.
  
  Parameters
  ----------
  detections : str
      File containing chords detections.
  annotations : str
      File containing chord annotations.
  name : str, optional
      Name of the evaluation object (e.g., the name of the song).
class_docstr_tok: ["Provide","various","chord","evaluation","scores",".","Parameters","--","--","--","--","--","detections",":","str","File","containing","chords","detections",".","annotations",":","str","File","containing","chord","annotations",".","name",":","str",",","optional","Name","of","the","evaluation","object","(","e.g.",",","the","name","of","the","song",")","."]
docstr: Length of annotations.
docstr_tok: ["Length","of","annotations","."]
code: def length(self):
      """Length of annotations."""
      return self.ann_chords["end"][-1] - self.ann_chords["start"][0]
  
imports: import numpy
  from .None import evaluation_io, EvaluationMixin
  from ..io import load_chords
label_desc: Use image node_id 2 for calling the ChordEvaluation obj's underlying member method code with example usage: obj.length() and returns: unknown