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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 AddLabel(self, label):
 """Adds a label to the event tag. Args: label (str):
 label. Raises: TypeError: if the label provided is not a string. ValueError: if a label is malformed. """

    if not isinstance(label, py2to3.STRING_TYPES):
      raise TypeError('label is not a string type. Is {0:s}'.format(
          type(label)))
    if not self._VALID_LABEL_REGEX.match(label):
      raise ValueError((
          'Unsupported label: "{0:s}". A label must only consist of '
          'alphanumeric characters or underscores.').format(label))

    if label not in self.labels:
      self.labels.append(label)