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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 index(self, name=None):
 # pylint: disable=C6409 """Returns index number of supplied column name. Args: name: string of column name. Raises: TableError: If name not found. Returns: Index of the specified header entry. """

    try:
      return self.header.index(name)
    except ValueError:
      raise TableError('Unknown index name %s.' % name)