def remove_label(label)
      unless label.valid?
        errors.add(:label, "is not valid.")
        return Trello.logger.warn "Label is not valid." unless label.valid?
      end
      client.delete("/cards/#{id}/idLabels/#{label.id}")
    end
def remove_label(label)
      unless label.valid?
        errors.add(:label, "is not valid.")
        return Trello.logger.warn "Label is not valid." unless label.valid?
      end
      client.delete("/cards/#{id}/idLabels/#{label.id}")
    end
Remove a label