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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 convert_to_dimension(d):
 """Converts input to a Dimension. Args: d: Dimension, tuple (string, int), or None. Returns: Dimension or None. Raises: ValueError: If d cannot be converted to a Dimension. """

  if d is None:
    return None
  if isinstance(d, Dimension):
    if not isinstance(d.name, str) or not isinstance(d.size, int):
      raise ValueError("Bad dimension %s" % (d,))
    return d
  name, size = d
  if isinstance(name, str) and isinstance(size, int):
    return Dimension(name, size)
  else:
    raise ValueError("could not convert %s to Dimension" % (d,))