class_docstr: Series/Frames plotting accessor and method.
  
  Uses the backend specified by the
  option ``plotting.backend``. By default, plotly is used.
  
  Plotting methods can also be accessed by calling the accessor as a method
  with the ``kind`` argument:
  ``s.plot(kind='hist')`` is equivalent to ``s.plot.hist()``
docstr: Find a pandas-on-Spark plotting backend
docstr_tok: ["Find","a","pandas-on-Spark","plotting","backend"]
code: def _find_backend(backend):
      """
      Find a pandas-on-Spark plotting backend
      """
      try:
          return PandasOnSparkPlotAccessor._backends[backend]
      except KeyError:
          try:
              module = importlib.import_module(backend)
          except ImportError:
              # We re-raise later on.
              pass
          else:
              if hasattr(module, "plot") or hasattr(
                  module, "plot_pandas_on_spark"
              ):
                  # Validate that the interface is implemented when the option
                  # is set, rather than at plot time.
                  PandasOnSparkPlotAccessor._backends[backend] = module
                  return module
  
      raise ValueError(
          "Could not find plotting backend '{backend}'. Ensure that you've installed "
          "the package providing the '{backend}' entrypoint, or that the package has a "
          "top-level `.plot` method.".format(backend=backend)
      )
  
imports: import importlib
  import pandas
  import numpy
  from pandas.core.base import PandasObject
  from pandas.core.dtypes.inference import is_integer
  from pyspark.ml.feature import Bucketizer
  from pyspark.mllib.stat import KernelDensity
  from pyspark.sql import functions
  from pyspark.pandas.missing import unsupported_function
  from pyspark.pandas.config import get_option
  from pyspark.pandas.utils import name_like_string
label_desc: Use image node_id 2 for calling the PandasOnSparkPlotAccessor obj's underlying member method code with example usage: obj._find_backend(backend) and returns: PandasOnSparkPlotAccessor, module