class_docstr: Calculates the number of 'True' values since the last `False` value.
  Description:
      From a series of Booleans, find the last record with a `False` value.
      Return the count of 'True' values between that record and the end of
      the series. Return nan if no values are `False`. Any nan values in the
      input are ignored. A 'False' value in the last row will result in a
      count of 0.
  Examples:
      >>> num_true_since_last_false = NumTrueSinceLastFalse()
      >>> num_true_since_last_false([False, True, False, True, True])
      2
code: def get_function(self):
      def num_true_since_last_false(x):
          x = x.dropna().astype(bool)
          false_indices = x[~x]
          if false_indices.empty:
              return np.nan
          last_false_index = false_indices.index[-1]
          x_slice = x.loc[last_false_index:]
          return x_slice.sum()
  
      return num_true_since_last_false
  
imports: import numpy
  from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import Boolean, IntegerNullable
  from featuretools.primitives.base import AggregationPrimitive
label_desc: Use image node_id 1 for calling the NumTrueSinceLastFalse obj's underlying member method code with example usage: obj.get_function() and returns: num_true_since_last_false, x_slice, np