class_docstr: Shifts an array of values by a specified number of periods.
  
  Args:
      periods (int): The number of periods by which to shift the input.
          Default is 1. Periods correspond to rows.
  
  Examples:
      >>> lag = Lag()
      >>> lag([1, 2, 3, 4, 5], pd.Series(pd.date_range(start="2020-01-01", periods=5, freq='D'))).tolist()
      [nan, 1.0, 2.0, 3.0, 4.0]
  
      You can specify the number of periods to shift the values
  
      >>> lag_periods = Lag(periods=3)
      >>> lag_periods([True, False, False, True, True], pd.Series(pd.date_range(start="2020-01-01", periods=5, freq='D'))).tolist()
      [nan, nan, nan, True, False]
code: def get_function(self):
      def lag(input_col, time_index):
          x = pd.Series(input_col.values, index=time_index.values)
          return x.shift(periods=self.periods, fill_value=None).values
  
      return lag
  
file_path: featuretools/featuretools/primitives/standard/transform/time_series/lag.py
imports: import pandas
  from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import Boolean, BooleanNullable
  from featuretools.primitives.base import TransformPrimitive
label_desc: Use image node_id 2 for calling the Lag obj's underlying member method code with example usage: obj.get_function() and returns: lag, x