code: def encode_cf_variable(var, needs_copy=True, name=None):
      
      ensure_not_multiindex(var, name=name)
  
      for coder in [times.CFDatetimeCoder(),
                    times.CFTimedeltaCoder(),
                    variables.CFScaleOffsetCoder(),
                    variables.CFMaskCoder(),
                    variables.UnsignedIntegerCoder()]:
          var = coder.encode(var, name=name)
  
      # TODO(shoyer): convert all of these to use coders, too:
      var = maybe_encode_nonstring_dtype(var, name=name)
      var = maybe_default_fill_value(var)
      var = maybe_encode_bools(var)
      var = ensure_dtype_not_object(var, name=name)
      return var
docs: Converts an Variable into an Variable which follows some
      of the CF conventions:
  
          - Nans are masked using _FillValue (or the deprecated missing_value)
          - Rescaling via: scale_factor and add_offset
          - datetimes are converted to the CF 'units since time' format
          - dtype encodings are enforced.
  
      Parameters
      ----------
      var : xarray.Variable
          A variable holding un-encoded data.
  
      Returns
      -------
      out : xarray.Variable
          A variable which has been encoded as described above.