code: def unstack(obj, level, fill_value=None):
      if isinstance(level, (tuple, list)):
          if len(level) != 1:
              # _unstack_multiple only handles MultiIndexes,
              # and isn't needed for a single level
              return _unstack_multiple(
                  obj, level, fill_value=fill_value
              )
          else:
              level = level[0]
  
      if isinstance(obj, DataFrame):
          if isinstance(obj.index, MultiIndex):
              return _unstack_frame(obj, level, fill_value=fill_value)
          else:
              return obj.T.stack(dropna=False)
      else:
          if is_extension_array_dtype(obj.dtype):
              return _unstack_extension_series(obj, level, fill_value)
          unstacker = _Unstacker(
              obj.values,
              obj.index,
              level=level,
              fill_value=fill_value,
              constructor=obj._constructor_expanddim,
          )
          return unstacker.get_result()
  
imports: from functools import partial
  import itertools
  import numpy
  from pandas._libs import algos, reshape
  from pandas._libs.sparse import IntIndex
  from pandas.compat import PY2, range, text_type, u, zip
  from pandas.core.dtypes.cast import maybe_promote
  from pandas.core.dtypes.common import ensure_platform_int, is_bool_dtype, is_extension_array_dtype, is_integer_dtype, is_list_like, is_object_dtype, needs_i8_conversion
  from pandas.core.dtypes.missing import notna
  from pandas import compat
  import pandas.core.algorithms
  from pandas.core.arrays import SparseArray
  from pandas.core.arrays.categorical import _factorize_from_iterable
  from pandas.core.frame import DataFrame
  from pandas.core.index import Index, MultiIndex
  from pandas.core.internals.arrays import extract_array
  from pandas.core.series import Series
  from pandas.core.sorting import compress_group_index, decons_obs_group_ids, get_compressed_ids, get_group_index
label_desc: Use image node_id 2 for calling a global function with example usage: unstack(obj, level, fill_value) and returns: unstacker, _unstack_multiple, _unstack_frame, obj, _unstack_extension_series