class_docstr: A file-like interface to features of a vector dataset
  
  Python text file objects are iterators over lines of a file. Fiona
  Collections are similar iterators (not lists!) over features
  represented as GeoJSON-like mappings.
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docstr: Returns an iterator over FIDs, optionally
  filtered by a test for spatial intersection with the provided
  ``bbox``, a (minx, miny, maxx, maxy) tuple or a geometry
  ``mask``. An attribute filter can be set using an SQL ``where``
  clause, which uses the `OGR SQL dialect
  <https://gdal.org/user/ogr_sql_dialect.html#where>`__.
  
  Positional arguments ``stop`` or ``start, stop[, step]`` allows
  iteration to skip over items or stop at a specific item.
  
  Note: spatial filtering using ``mask`` may be inaccurate and returning
  all features overlapping the envelope of ``mask``.
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code: def keys(self, *args, **kwds):
      """Returns an iterator over FIDs, optionally
      filtered by a test for spatial intersection with the provided
      ``bbox``, a (minx, miny, maxx, maxy) tuple or a geometry
      ``mask``. An attribute filter can be set using an SQL ``where``
      clause, which uses the `OGR SQL dialect
      <https://gdal.org/user/ogr_sql_dialect.html#where>`__.
  
      Positional arguments ``stop`` or ``start, stop[, step]`` allows
      iteration to skip over items or stop at a specific item.
  
      Note: spatial filtering using ``mask`` may be inaccurate and returning
      all features overlapping the envelope of ``mask``.
      """
      if self.closed:
          raise ValueError("I/O operation on closed collection")
      elif self.mode != "r":
          raise OSError("collection not open for reading")
      if args:
          s = slice(*args)
          start = s.start
          stop = s.stop
          step = s.step
      else:
          start = stop = step = None
      bbox = kwds.get("bbox")
      mask = kwds.get("mask")
      if bbox and mask:
          raise ValueError("mask and bbox can not be set together")
      where = kwds.get("where")
      self.iterator = KeysIterator(
          self, start, stop, step, bbox, mask, where
      )
      return self.iterator
  
imports: from contextlib import ExitStack
  import logging
  import os
  import warnings
  from fiona import compat, vfs
  from fiona.ogrext import Iterator, ItemsIterator, KeysIterator
  from fiona.ogrext import Session, WritingSession
  from fiona.ogrext import buffer_to_virtual_file, remove_virtual_file, GEOMETRY_TYPES
  from fiona.errors import DriverError, DriverSupportError, GDALVersionError, SchemaError, UnsupportedGeometryTypeError, UnsupportedOperation
  from fiona.logutils import FieldSkipLogFilter
  from fiona.crs import CRS
  from fiona._env import get_gdal_release_name, get_gdal_version_tuple
  from fiona.env import env_ctx_if_needed
  from fiona.errors import FionaDeprecationWarning
  from fiona.drvsupport import driver_from_extension, supported_drivers, driver_mode_mingdal, _driver_converts_field_type_silently_to_str, _driver_supports_field
  from fiona.path import Path, vsi_path, parse_path
label_desc: Use image node_id 15 for calling the Collection obj's underlying member method code with example usage: obj.keys() and returns: self