# Instead of using the terms "url" or "file", we use the more general
# term "reader" to indicate an open file or webpage.

def display_lines(r):
    '''Display the lines of the file/webpage (with leading and trailing
    whitespace removed) from open reader r.'''

def display_lines_with_text(r, text):
    '''Display the lines of the file/webpage (with leading and trailing
    whitespace removed) from open reader r that contain the str text.'''

def copy_file(r):
    '''Write the lines of open reader r to the file copy.txt.'''
    
if __name__ == '__main__':

    data_file = open('data.txt')
    display_lines(data_file)
    data_file.close()

    data_file = open('data.txt')
    display_lines_with_text(data_file, 'ene')
    data_file.close()

    data_file = open('data.txt')
    copy_file(data_file)
    data_file.close()