<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def as_lines(self):
 """Return a Lines representation as a string"""


        out_lines = []
        for t,v in self.lines:

            # Make the output prettier
            if t == 'Section':
                out_lines.append('')

            out_lines.append('{}: {}'.format(t,v if v is not None else '') )

        return '\n'.join(out_lines)