input: def linear_regression_model():
      """
      Write a code snippet for a simple linear regression model in Python.
      >>> import pandas as pd
      >>> import matplotlib.pyplot as plt
      >>> from sklearn import linear_model
      >>> 
      >>> # Read data from CSV
      >>> data = pd.read_csv('data.csv')
      >>> 
      >>> # Set X and Y
      >>> X = data['X']
      >>> Y = data['Y']
      >>> 
      >>> # Create linear regression model
      >>> model = linear_model.LinearRegression()
      >>> 
      >>> # Train the model
      >>> model.fit(X, Y)
      >>> 
      >>> # Make predictions
      >>> Y_pred = model.predict(X)
      >>> 
      >>> # Visualize the results
      >>> plt.scatter(X, Y)
      >>> plt.plot(X, Y_pred, color='red')
      >>> plt.show()
      """
output:     import pandas as pd
      import matplotlib.pyplot as plt
      from sklearn import linear_model
      
      # Read data from CSV
      data = pd.read_csv('data.csv')
      
      # Set X and Y
      X = data[['X']]
      Y = data['Y']
      
      # Create linear regression model
      model = linear_model.LinearRegression()
      
      # Train the model
      model.fit(X, Y)
      
      # Make predictions
      Y_pred = model.predict(X)
      
      # Visualize the results
      plt.scatter(X, Y)
      plt.plot(X, Y_pred, color='red')
      plt.show()