code: func (c *Collection) Remove(selector interface{}) error {
  	lerr, err := c.writeQuery(&deleteOp{c.FullName, selector, 1})
  	if err == nil && lerr != nil && lerr.N == 0 {
  		return ErrNotFound
  	}
  	return err
  }
docs: // Remove finds a single document matching the provided selector document
  // and removes it from the database.
  // If the session is in safe mode (see SetSafe) a ErrNotFound error is
  // returned if a document isn't found, or a value of type *LastError
  // when some other error is detected.
  //
  // Relevant documentation:
  //
  //     http://www.mongodb.org/display/DOCS/Removing
  //