text: # BSD 3-Clause License; see https://github.com/scikit-hep/awkward-1.0/blob/main/LICENSE
  
  import awkward as ak
  
  np = ak.nplike.NumpyMetadata.instance()
  
  
  def firsts(array, axis=1, highlevel=True, behavior=None):
      raise ak._v2._util.error(NotImplementedError)
  
  
  #     """
  #     Args:
  #         array: Data from which to select the first elements from nested lists.
  #         axis (int): The dimension at which this operation is applied. The
  #             outermost dimension is `0`, followed by `1`, etc., and negative
  #             values count backward from the innermost: `-1` is the innermost
  #             dimension, `-2` is the next level up, etc.
  #         highlevel (bool): If True, return an #ak.Array; otherwise, return
  #             a low-level #ak.layout.Content subclass.
  #         behavior (None or dict): Custom #ak.behavior for the output array, if
  #             high-level.
  
  #     Selects the first element of each non-empty list and inserts None for each
  #     empty list.
  
  #     For example,
  
  #         >>> array = ak.Array([[1.1], [2.2], [], [3.3], [], [], [4.4], [5.5]])
  #         >>> print(ak.firsts(array))
  #         [1.1, 2.2, None, 3.3, None, None, 4.4, 5.5]
  
  #     See #ak.singletons to invert this function.
  #     """
  #     layout = ak._v2.operations.convert.to_layout(
  #         array, allow_record=False, allow_other=False
  #     )
  #     if isinstance(layout, ak.partition.PartitionedArray):   # NO PARTITIONED ARRAY
  #         posaxis = None
  #         for x in layout.partitions:
  #             if posaxis is None:
  #                 posaxis = x.axis_wrap_if_negative(axis)
  #             elif posaxis != x.axis_wrap_if_negative(axis):
  #                 raise ak._v2._util.error(ValueError(
  #                     "ak.firsts for partitions with different axis depths"
  #
  #                 ))
  #     else:
  #         posaxis = layout.axis_wrap_if_negative(axis)
  
  #     if posaxis == 0:
  #         if len(layout) == 0:
  #             out = None
  #         else:
  #             out = layout[0]
  #     else:
  #         if posaxis < 0:
  #             raise ak._v2._util.error(NotImplementedError(
  #                 "ak.firsts with ambiguous negative axis"
  #
  #             ))
  #         toslice = (slice(None, None, None),) * posaxis + (0,)
  #         out = ak.mask(layout, ak.num(layout, axis=posaxis) > 0, highlevel=False)[
  #             toslice
  #         ]
  
  #     return ak._v2._util.maybe_wrap_like(out, array, behavior, highlevel)
  