class_docstr: A trainer that train the model.
  
  Attributes:
      _model: Model.
      _preprocessor: Transformer. Preprocessing data for feature extraction.
code: def __init__(self, model, preprocessor=None):
      self._model = model
      self._preprocessor = preprocessor
  
imports: from ....imports import *
  from .callbacks import F1score
  from .utils import AnagoNERSequence
label_desc: Use image node_id 1 to create a new Trainer object from inherited base classes: object with example: obj = Trainer(model, preprocessor)