code: func (t *Transaction) deleteFieldIndexes(c *Collection, id string) {
  	for _, fs := range c.spec.fields {
  		switch fs.indexKind {
  		case noIndex:
  			continue
  		case numericIndex, booleanIndex:
  			t.deleteNumericOrBooleanIndex(fs, c.spec, id)
  		case stringIndex:
  			// NOTE: this invokes a lua script which is defined in scripts/delete_string_index.lua
  			t.deleteStringIndex(c.Name(), id, fs.redisName)
  		}
  	}
  }
docs: // deleteFieldIndexes adds commands to the transaction for deleting the field
  // indexes for all indexed fields of the given model type.