class_docstr: Calculates the cumulative count.
  
  Description:
      Given a list of values, return the cumulative count
      (or running count). There is no set window, so the
      count at each point is calculated over all prior
      values. `NaN` values are counted.
  
  Examples:
      >>> cum_count = CumCount()
      >>> cum_count([1, 2, 3, 4, None, 5]).tolist()
      [1, 2, 3, 4, 5, 6]
code: def get_function(self):
      def cum_count(values):
          return np.arange(1, len(values) + 1)
  
      return cum_count
  
imports: import numpy
  from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import IntegerNullable
  from featuretools.primitives.base import TransformPrimitive
label_desc: Use image node_id 1 for calling the CumCount obj's underlying member method code with example usage: obj.get_function() and returns: cum_count, np