Python中为什么会显示没有定义model

from sklearn.model_selection import GridSearchCV
from sklearn.linear_model import LogisticRegression
from sklearn.feature_selection import SelectFromModel
from sklearn.metrics import f1_score
from sklearn.model_selection import KFold
model.fit(X_train,y_train)
GridSearchCV(cv=KFold(n_splits=4, random_state=None, shuffle=False),
       error_score='raise-deprecating',
       estimator=LogisticRegression(C=1.0, class_weight=None, dual=False, fit_intercept=True,
          intercept_scaling=1, max_iter=100, multi_class='warn',
          n_jobs=None, penalty='l1', random_state=None, solver='warn',
          tol=0.0001, verbose=0, warm_start=False),
       fit_params=None, iid='warn', n_jobs=3,
       param_grid={'C': array([1.00000e-04, 3.59381e-04, 1.29155e-03, 4.64159e-03, 1.66810e-02,
       5.99484e-02, 2.15443e-01, 7.74264e-01, 2.78256e+00, 1.00000e+01])},
       pre_dispatch='2*n_jobs', refit=True, return_train_score='warn',
       scoring=None, verbose=0)

Traceback (most recent call last):
  File "D:/CAS/Python/;;lunwen/02.py", line 6, in <module>
    model.fit(X_train,y_train)
NameError: name 'model' is not defined

你没定义model啊
你第六行用到了model
但是你前五行哪有定义它呀