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"""
Important classes of Spark SQL and DataFrames:

    - :class:`pyspark.sql.SQLContext`
      Main entry point for :class:`DataFrame` and SQL functionality.
    - :class:`pyspark.sql.DataFrame`
      A distributed collection of data grouped into named columns.
    - :class:`pyspark.sql.Column`
      A column expression in a :class:`DataFrame`.
    - :class:`pyspark.sql.Row`
      A row of data in a :class:`DataFrame`.
    - :class:`pyspark.sql.HiveContext`
      Main entry point for accessing data stored in Apache Hive.
    - :class:`pyspark.sql.GroupedData`
      Aggregation methods, returned by :func:`DataFrame.groupBy`.
    - :class:`pyspark.sql.DataFrameNaFunctions`
      Methods for handling missing data (null values).
    - :class:`pyspark.sql.DataFrameStatFunctions`
      Methods for statistics functionality.
    - :class:`pyspark.sql.functions`
      List of built-in functions available for :class:`DataFrame`.
    - :class:`pyspark.sql.types`
      List of data types available.
    - :class:`pyspark.sql.Window`
      For working with window functions.
"""
from __future__ import absolute_import


def since(version):
    """
    A decorator that annotates a function to append the version of Spark the function was added.
    """
    import re
    indent_p = re.compile(r'\n( +)')

    def deco(f):
        indents = indent_p.findall(f.__doc__)
        indent = ' ' * (min(len(m) for m in indents) if indents else 0)
        f.__doc__ = f.__doc__.rstrip() + "\n\n%s.. versionadded:: %s" % (indent, version)
        return f
    return deco


from pyspark.sql.types import Row
from pyspark.sql.context import SQLContext, HiveContext
from pyspark.sql.column import Column
from pyspark.sql.dataframe import DataFrame, SchemaRDD, DataFrameNaFunctions, DataFrameStatFunctions
from pyspark.sql.group import GroupedData
from pyspark.sql.readwriter import DataFrameReader, DataFrameWriter
from pyspark.sql.window import Window, WindowSpec


__all__ = [
    'SQLContext', 'HiveContext', 'DataFrame', 'GroupedData', 'Column', 'Row',
    'DataFrameNaFunctions', 'DataFrameStatFunctions', 'Window', 'WindowSpec',
    'DataFrameReader', 'DataFrameWriter'
]