class_docstr: Determines the number of unique days.
  
  Description:
      Given a list of datetimes, return the number of unique days.
      The same day in two different years is treated as different. So
      Feb 21, 2017 is different than Feb 21, 2019, even though they are
      both the 21st of February.
  
  Examples:
      >>> from datetime import datetime
      >>> n_unique_days = NUniqueDays()
      >>> times = [datetime(2019, 2, 1),
      ...          datetime(2019, 2, 1),
      ...          datetime(2018, 2, 1),
      ...          datetime(2019, 1, 1)]
      >>> n_unique_days(times)
      3
class_docstr_tok: ["Determines","the","number","of","unique","days",".","Description",":","Given","a","list","of","datetimes",",","return","the","number","of","unique","days",".","The","same","day","in","two","different","years","is","treated","as","different",".","So","Feb","21",",","2017","is","different","than","Feb","21",",","2019",",","even","though","they","are","both","the","21st","of","February",".","Examples",":",">",">",">","from","datetime","import","datetime",">",">",">","n_unique_days","=","NUniqueDays","(",")",">",">",">","times","=","[","datetime","(","2019",",","2",",","1",")",",","...","datetime","(","2019",",","2",",","1",")",",","...","datetime","(","2018",",","2",",","1",")",",","...","datetime","(","2019",",","1",",","1",")","]",">",">",">","n_unique_days","(","times",")","3"]
code: def get_function(self):
      def n_unique_days(x):
          return x.dt.floor("D").nunique()
  
      return n_unique_days
  
imports: from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import Datetime, Integer
  from featuretools.primitives.base import AggregationPrimitive
label_desc: Use image node_id 1 for calling the NUniqueDays obj's underlying member method code with example usage: obj.get_function() and returns: n_unique_days, x