名为"Metadata“的字典字段

import json

# 假设我们有一个包含元数据的字典
metadata = {
    "name": "example",
    "version": "1.0",
    "author": "John Doe",
    "created_at": "2023-04-01"
}

# 验证元数据字段
def validate_metadata(metadata):
    required_fields = ["name", "version", "author", "created_at"]
    for field in required_fields:
        if field not in metadata:
            raise ValueError(f"Missing required field: {field}")
    return True

# 更新元数据字段
def update_metadata(metadata, field, value):
    if field in metadata:
        metadata[field] = value
    else:
        raise KeyError(f"Field '{field}' does not exist in metadata")

# 示例：验证元数据
try:
    validate_metadata(metadata)
    print("Metadata validation passed.")
except ValueError as e:
    print(e)

# 示例：更新元数据字段
try:
    update_metadata(metadata, "version", "1.1")
    print("Metadata updated successfully:", json.dumps(metadata, indent=4))
except KeyError as e:
    print(e)