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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def unindent(lines):
    '''Convert an iterable of indented lines into a sequence of tuples.

    The first element of each tuple is the indent in number of characters, and
    the second element is the unindented string.

    Args:
        lines: A sequence of strings representing the lines of text in a docstring.

    Returns:
        A list of tuples where each tuple corresponds to one line of the input
        list. Each tuple has two entries - the first is an integer giving the
        size of the indent in characters, the second is the unindented text.
    '''
    unindented_lines = []
    for line in lines:
        unindented_line = line.lstrip()
        indent = len(line) - len(unindented_line)
        unindented_lines.append((indent, unindented_line))
    return unindented_lines