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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 _find_channel_index(data_format):
 """Returns the index of the channel dimension. Args: data_format: A string of characters corresponding to Tensor dimensionality. Returns: channel_index: An integer indicating the channel dimension. Raises: ValueError: If no channel dimension was found. """

  for i, c in enumerate(data_format):
    if c == "C":
      return i
  raise ValueError("data_format requires a channel dimension. Got: {}"
                   .format(data_format))