class_docstr: Determines the is_quarter_start attribute of a datetime column.
  
  Examples:
      >>> from datetime import datetime
      >>> iqs = IsQuarterStart()
      >>> dates = [datetime(2020, 3, 31),
      ...          datetime(2020, 1, 1)]
      >>> iqs(dates).tolist()
      [False, True]
code: def get_function(self):
      def is_quarter_start(vals):
          return vals.dt.is_quarter_start
  
      return is_quarter_start
  
imports: from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import BooleanNullable, Datetime
  from featuretools.primitives.base import TransformPrimitive
  from featuretools.utils.gen_utils import Library
label_desc: Use image node_id 1 for calling the IsQuarterStart obj's underlying member method code with example usage: obj.get_function() and returns: is_quarter_start, vals