<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def reduce_to_2d(arr):
 """Given a np.npdarray with nDims > 2, reduce it to 2d. It does this by selecting the zeroth coordinate for every dimension greater than two. Args: arr: a numpy ndarray of dimension at least 2. Returns: A two-dimensional subarray from the input array. Raises: ValueError: If the argument is not a numpy ndarray, or the dimensionality is too low. """

  if not isinstance(arr, np.ndarray):
    raise ValueError('reduce_to_2d requires a numpy.ndarray')

  ndims = len(arr.shape)
  if ndims < 2:
    raise ValueError('reduce_to_2d requires an array of dimensionality >=2')
  # slice(None) is equivalent to `:`, so we take arr[0,0,...0,:,:]
  slices = ([0] * (ndims - 2)) + [slice(None), slice(None)]
  return arr[slices]