PCA用于可视化

def solve():
    import matplotlib
    matplotlib.use(____)
    import matplotlib.pyplot as plt
    from sklearn.datasets import load_digits
    from sklearn.decomposition import PCA
    from sklearn.preprocessing import StandardScaler
    digits = load_digits()
    X = digits.data
    y = digits.target
    scaler = StandardScaler()
    X_s = scaler.fit_transform(____)
    pca = PCA(____)
    X_pca = pca.fit_transform(____)
    plt.figure(figsize=(____, ____))
    scatter = plt.scatter(____)
    plt.colorbar(____)
    plt.title(____)
    plt.tight_layout()
    plt.show()
    print(____)