func IsDate(str string) bool {
	matches := rxDate.FindAllStringSubmatch(str, -1)
	if len(matches) == 0 || len(matches[0]) == 0 {
		return false
	}
	m := matches[0]
	return !(m[2] < "01" || m[2] > "12" || m[3] < "01" || m[3] > "31")
}
IsDate returns true when the string is a valid date
package strfmt
import (
	"database/sql/driver"
	"errors"
	"fmt"
	"regexp"
	"time"
	"gopkg.in/mgo.v2/bson"
	"github.com/mailru/easyjson/jlexer"
	"github.com/mailru/easyjson/jwriter"
)
func init() {
	d := Date{}
	Default.Add("date", &d, IsDate)
}