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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 next(self):
    " Move on to the next character in the text. "

    char = self.char
    if char == '\n':
      self.lineno += 1
      self.colno = 0
    else:
      self.colno += 1
    self.index += 1
    return self.char