class_docstr: Construct new channel by blending contributions from a set of channels.
  
  This class can be used to compute weighted average of different channels.
  Primarily it's used to correct the green band of AHI and FCI in order to
  allow for proper true color imagery.
  
  Below is an example used to generate a corrected green channel for AHI using a weighted average from
  three channels, with 63% contribution from the native green channel (B02), 29% from the red channel (B03)
  and 8% from the near-infrared channel (B04)::
  
    corrected_green:
      compositor: !!python/name:satpy.composites.spectral.SpectralBlender
      fractions: [0.63, 0.29, 0.08]
      prerequisites:
        - name: B02
          modifiers: [sunz_corrected, rayleigh_corrected]
        - name: B03
          modifiers: [sunz_corrected, rayleigh_corrected]
        - name: B04
          modifiers: [sunz_corrected, rayleigh_corrected]
      standard_name: toa_bidirectional_reflectance
  
  Other examples can be found in the``ahi.yaml`` composite file in the satpy distribution.
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docstr: Set default keyword argument values.
docstr_tok: ["Set","default","keyword","argument","values","."]
code: def __init__(self, *args, fractions=(), **kwargs):
      """Set default keyword argument values."""
      self.fractions = fractions
      super().__init__(*args, **kwargs)
  
file_path: satpy/satpy/composites/spectral.py
imports: import logging
  from satpy.composites import GenericCompositor
  from satpy.dataset import combine_metadata
label_desc: Use image node_id 1 to create a new SpectralBlender object from inherited base classes: GenericCompositor with example: obj = SpectralBlender()