<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def prepend_line(filepath, line):
 """Rewrite a file adding a line to its beginning. """

    with open(filepath) as f:
        lines = f.readlines()

    lines.insert(0, line)

    with open(filepath, 'w') as f:
        f.writelines(lines)