class_docstr: The internal field to store the dtype as well as the Spark's StructField optionally.
  
  Parameters
  ----------
  dtype : numpy.dtype or pandas' ExtensionDtype
      The dtype for the field
  struct_field : StructField, optional
      The `StructField` for the field. If None, InternalFrame will properly set.
class_docstr_tok: ["The","internal","field","to","store","the","dtype","as","well","as","the","Spark","'s","StructField","optionally",".","Parameters","--","--","--","--","--","dtype",":","numpy.dtype","or","pandas","'","ExtensionDtype","The","dtype","for","the","field","struct_field",":","StructField",",","optional","The","`","StructField","`","for","the","field",".","If","None",",","InternalFrame","will","properly","set","."]
docstr: Return the nullability for the field if the StructField exists.
docstr_tok: ["Return","the","nullability","for","the","field","if","the","StructField","exists","."]
code: def nullable(self) -> bool:
      """Return the nullability for the field if the StructField exists."""
      assert self.struct_field is not None
      return self.struct_field.nullable
  
imports: import re
  from typing import Any, Dict, List, Optional, Sequence, Tuple, Union, TYPE_CHECKING, cast
  import numpy
  import pandas
  from pandas.api.types import CategoricalDtype
  from pyspark._globals import _NoValue, _NoValueType
  from pyspark.sql import functions, Column, DataFrame, Window
  from pyspark.sql.types import BooleanType, DataType, LongType, StructField, StructType, StringType
  from pyspark.sql.utils import is_timestamp_ntz_preferred
  from pyspark.sql.utils import is_remote, get_column_class, get_dataframe_class
  from pyspark import pandas
  from pyspark.pandas._typing import Label
  from pyspark.pandas.spark.utils import as_nullable_spark_type, force_decimal_precision_scale
  from pyspark.pandas.data_type_ops.base import DataTypeOps
  from pyspark.pandas.typedef import Dtype, as_spark_type, extension_dtypes, infer_pd_series_spark_type, spark_type_to_pandas_dtype
  from pyspark.pandas.utils import column_labels_level, default_session, is_name_like_tuple, is_testing, lazy_property, name_like_string, scol_for, spark_column_equals
label_desc: Use image node_id 7 for calling the InternalField obj's underlying member method code with example usage: obj.nullable() and returns: self