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  """
  Apache Beam SDK for Python
  ==========================
  
  `Apache Beam <https://beam.apache.org>`_ provides a simple, powerful programming
  model for building both batch and streaming parallel data processing pipelines.
  
  The Apache Beam SDK for Python provides access to Apache Beam capabilities
  from the Python programming language.
  
  Status
  ------
  The SDK is still early in its development, and significant changes
  should be expected before the first stable version.
  
  Overview
  --------
  The key concepts in this programming model are
  
  * :class:`~apache_beam.pvalue.PCollection`: represents a collection of data,
    which could be bounded or unbounded in size.
  * :class:`~apache_beam.transforms.ptransform.PTransform`: represents a
    computation that transforms input PCollections into output PCollections.
  * :class:`~apache_beam.pipeline.Pipeline`: manages a directed acyclic graph of
    :class:`~apache_beam.transforms.ptransform.PTransform` s and
    :class:`~apache_beam.pvalue.PCollection` s that is ready for execution.
  * :class:`~apache_beam.runners.runner.PipelineRunner`: specifies where and how
    the pipeline should execute.
  * :class:`~apache_beam.io.iobase.Read`: read from an external source.
  * :class:`~apache_beam.io.iobase.Write`: write to an external data sink.
  
  Typical usage
  -------------
  At the top of your source file::
  
    import apache_beam as beam
  
  After this import statement
  
  * Transform classes are available as
    :class:`beam.FlatMap <apache_beam.transforms.core.FlatMap>`,
    :class:`beam.GroupByKey <apache_beam.transforms.core.GroupByKey>`, etc.
  * Pipeline class is available as
    :class:`beam.Pipeline <apache_beam.pipeline.Pipeline>`
  * Text read/write transforms are available as
    :class:`beam.io.ReadFromText <apache_beam.io.textio.ReadFromText>`,
    :class:`beam.io.WriteToText <apache_beam.io.textio.WriteToText>`.
  
  Examples
  --------
  The `examples subdirectory
  <https://github.com/apache/beam/tree/master/sdks/python/apache_beam/examples>`_
  has some examples.
  
  """
  
  
  from __future__ import absolute_import
  
  import sys
  import os
  
  
  if not ((sys.version_info[0] == 2 and sys.version_info[1] == 7) or
          (sys.version_info[0] == 3 and os.environ['BEAM_EXPERIMENTAL_PY3'])):
    raise RuntimeError(
        'The Apache Beam SDK for Python is supported only on Python 2.7. '
        'It is not supported on Python ['+ str(sys.version_info) + '].')
  
  # pylint: disable=wrong-import-position
  import apache_beam.internal.pickler
  
  from apache_beam import coders
  from apache_beam import io
  from apache_beam import typehints
  from apache_beam import version
  from apache_beam.pipeline import Pipeline
  from apache_beam.transforms import *
  # pylint: enable=wrong-import-position
  
  __version__ = version.__version__
  