You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: validate.rs
    path of file: ./repos/qdrant/lib/api/src/grpc
    
    the code of the file until where you have to start completion: use std::borrow::Cow;
use std::collections::HashMap;

use common::validation::{validate_move_shard_different_peers, validate_range_generic};
use validator::{Validate, ValidationError, ValidationErrors};

use super::qdrant as grpc;

const TIMESTAMP_MIN_SECONDS: i64 = -62_135_596_800; // 0001-01-01T00:00:00Z
const TIMESTAMP_MAX_SECONDS: i64 = 253_402_300_799; // 9999-12-31T23:59:59Z

pub trait ValidateExt {
    fn validate(&self) -> Result<(), ValidationErrors>;
}

impl Validate for dyn ValidateExt {
    #[inline]
    fn validate(&self) -> Result<(), ValidationErrors> {
        ValidateExt::validate(se
    
    fn validate(&self) -> Result<(), ValidationErrors> {
        let grpc::FieldCondition {
            key: _,
            r#match,
            range,
            datetime_range,
            geo_bounding_box,
            geo_radius,
            geo_polygon,
            values_count,
        } = self;

        let all_fields_none = r#match.is_none()
            && range.is_none()
            && datetime_range.is_none()
            && geo_bounding_box.is_none()
            && geo_radius.is_none()
            && geo_polygon.is_none()
            && values_count.is_none();

        if all_fields_none {
            let mut errors = ValidationErrors::new();
            errors.add(
                "match",
                ValidationError::new("At least one field condition must be specified"),
            );
            Err(errors)
        } else {
            Ok(())
        }
    }