class_docstr: common ops mixin to support a unified interface datetimelike Index
class_docstr_tok: ["common","ops","mixin","to","support","a","unified","interface","datetimelike","Index"]
code: def unique(self, level=None):
      if level is not None:
          self._validate_index_level(level)
  
      result = self._data.unique()
  
      # Note: if `self` is already unique, then self.unique() should share
      #  a `freq` with self.  If not already unique, then self.freq must be
      #  None, so again sharing freq is correct.
      return self._shallow_copy(result._data)
  
imports: import operator
  import warnings
  import numpy
  from pandas._libs import NaT, iNaT, lib
  from pandas.compat.numpy import function
  from pandas.errors import AbstractMethodError
  from pandas.util._decorators import Appender, cache_readonly, deprecate_kwarg
  from pandas.core.dtypes.common import ensure_int64, is_dtype_equal, is_float, is_integer, is_list_like, is_period_dtype, is_scalar
  from pandas.core.dtypes.generic import ABCIndex, ABCIndexClass, ABCSeries
  from pandas.core import algorithms, ops
  from pandas.core.accessor import PandasDelegate
  from pandas.core.arrays import ExtensionOpsMixin
  from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin, _ensure_datetimelike_to_i8
  import pandas.core.indexes.base
  from pandas.core.indexes.base import Index, _index_shared_docs
  from pandas.core.tools.timedeltas import to_timedelta
  import pandas.io.formats.printing
label_desc: Use image node_id 4 for calling the DatetimeIndexOpsMixin obj's underlying member method code with example usage: obj.unique(level) and returns: self