class_docstr: Parameters
  ----------
  data : A tuple of four cudf.Series of list dtype
  meta : A GeoMeta object (optional)
  
  Notes
  -----
  The GeoColumn class subclasses `NumericalColumn`. Combined with
  `_copy_type_metadata`, this assures support for sort, groupby,
  and potential other `cudf` algorithms.
class_docstr_tok: ["Parameters","--","--","--","--","--","data",":","A","tuple","of","four","cudf.Series","of","list","dtype","meta",":","A","GeoMeta","object","(","optional",")","Notes","--","--","-","The","GeoColumn","class","subclasses","`","NumericalColumn","`",".","Combined","with","`","_copy_type_metadata","`",",","this","assures","support","for","sort",",","groupby",",","and","potential","other","`","cudf","`","algorithms","."]
docstr: Returns the number of unique geometries stored in this GeoColumn.
docstr_tok: ["Returns","the","number","of","unique","geometries","stored","in","this","GeoColumn","."]
code: def __len__(self):
      """
      Returns the number of unique geometries stored in this GeoColumn.
      """
      return len(self._meta.input_types)
  
imports: from enum import Enum
  from functools import cached_property
  from typing import Tuple, TypeVar
  import cupy
  import pyarrow
  import cudf
  from cudf.core.column import ColumnBase, as_column, build_list_column
  from cuspatial.core._column.geometa import Feature_Enum, GeoMeta
  from cuspatial.utils.column_utils import empty_geometry_column
label_desc: Use image node_id 3 for calling the GeoColumn obj's underlying member method code with example usage: obj.__len__() and returns: len