code: def enforce_cf_variable(var, mask_and_scale=True):
      
      var = as_variable(var)
      data = var._data  # avoid loading by accessing _data instead of data
      dims = var.dims
      attrs = var.attrs.copy()
      encoding = var.encoding.copy()
      orig_dtype = data.dtype
  
      # Process masking/scaling coordinates. We only expect a "scale" value
      # for the units with this output.
      if 'scale' in attrs:
          scale = attrs.pop('scale')
          attrs['scale_factor'] = scale
          encoding['scale_factor'] = scale
  
          # TODO: Once the xr.decode_cf bug is fixed, we won't need to manually
          #       handle masking/scaling
          if mask_and_scale:
              data = scale*data
  
      # Process units
      # TODO: How do we want to handle parts-per-* units? These are not part of
      #       the udunits standard, and the CF conventions suggest using units
      #       like 1e-6 for parts-per-million. But we potentially mix mass and
      #       volume/molar mixing ratios in GEOS-Chem output, so we need a way
      #       to handle that edge case.
      if 'unit' in attrs:
          unit = attrs.pop('unit')
          unit = get_cfcompliant_units(unit)
          attrs['units'] = unit
  
      # TODO: Once the xr.decode_cf bug is fixed, we won't need to manually
      #       handle masking/scaling
      return Variable(dims, data, attrs, encoding=encoding)
docs: Given a Variable constructed from GEOS-Chem output, enforce
      CF-compliant metadata and formatting.
  
      Until a bug with lazily-loaded data and masking/scaling is resolved in
      xarray, you have the option to manually mask and scale the data here.
  
      Parameters
      ----------
      var : xarray.Variable
          A variable holding information decoded from GEOS-Chem output.
      mask_and_scale : bool
          Flag to scale and mask the data given the unit conversions provided
  
      Returns
      -------
      out : xarray.Variable
          The original variable processed to conform to CF standards
  
      .. note::
  
          This method borrows heavily from the ideas in ``xarray.decode_cf_variable``