I am plotting the data with histogram, however I see odd color which I did not assign. Is there hindden data behind?
def plot_train_test_hist(train_df, val_df,test_df,bins=1000, colname='exp_mean'):
    ''' Check distribution of train/test scores, sanity check that its not skewed'''
    plt.hist(train_df[colname].values,bins=bins,label='train',alpha=0.7)
    plt.hist(val_df[colname].values,bins=bins,label='val',alpha=0.5)
    plt.hist(test_df[colname].values,bins=bins,label='test',alpha=0.4)
    plt.legend()
    plt.xlabel(colname,fontsize=14)
    plt.ylabel("Count",fontsize=14)
    plt.suptitle("Histogram of dataset")
    plt.title('w/o masking in Log',size= 'small')
    plt.show()

 
     
    