code: func SynthBody(filename string, values map[string]cty.Value) hcl.Body {
  	return synthBody{
  		Filename: filename,
  		Values:   values,
  	}
  }
docs: // SynthBody produces a synthetic hcl.Body that behaves as if it had attributes
  // corresponding to the elements given in the values map.
  //
  // This is useful in situations where, for example, values provided on the
  // command line can override values given in configuration, using MergeBodies.
  //
  // The given filename is used in case any diagnostics are returned. Since
  // the created body is synthetic, it is likely that this will not be a "real"
  // filename. For example, if from a command line argument it could be
  // a representation of that argument's name, such as "-var=...".