class_docstr: Computes the time since the previous entry in a list.
  
  Args:
      unit (str): Defines the unit of time to count from.
          Defaults to Seconds. Acceptable values:
          years, months, days, hours, minutes, seconds, milliseconds, nanoseconds
  
  Description:
      Given a list of datetimes, compute the time in seconds elapsed since
      the previous item in the list. The result for the first item in the
      list will always be `NaN`.
  
  Examples:
      >>> from datetime import datetime
      >>> time_since_previous = TimeSincePrevious()
      >>> dates = [datetime(2019, 3, 1, 0, 0, 0),
      ...          datetime(2019, 3, 1, 0, 2, 0),
      ...          datetime(2019, 3, 1, 0, 3, 0),
      ...          datetime(2019, 3, 1, 0, 2, 30),
      ...          datetime(2019, 3, 1, 0, 10, 0)]
      >>> time_since_previous(dates).tolist()
      [nan, 120.0, 60.0, -30.0, 450.0]
code: def get_function(self):
      def pd_diff(values):
          return convert_time_units(
              values.diff().apply(lambda x: x.total_seconds()),
              self.unit,
          )
  
      return pd_diff
  
file_path: featuretools/featuretools/primitives/standard/transform/datetime/time_since_previous.py
imports: from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import Datetime
  from featuretools.primitives.base import TransformPrimitive
  from featuretools.utils import convert_time_units
label_desc: Use image node_id 2 for calling the TimeSincePrevious obj's underlying member method code with example usage: obj.get_function() and returns: pd_diff, convert_time_units