{
  "resourceType": "StructureDefinition",
  "url": "https://example.org/fhir/StructureDefinition/MyModel",
  "name": "MyModel",
  "status": "draft",
  "fhirVersion": "5.0.0",
  "kind": "logical",
  "abstract": false,
  "type": "https://example.org/fhir/StructureDefinition/MyModel",
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Element",
  "derivation": "specialization",
  "differential": {
    "element": [
      {
        "id": "MyModel",
        "path": "MyModel",
        "min": 0,
        "max": "*",
        "type": [
          {
            "code": "Element"
          }
        ]
      },
      {
        "id": "MyModel.email",
        "path": "MyModel.email",
        "min": 0,
        "max": "*",
        "type": [
          {
            "code": "string",
            "profile": [
              "http://hl7.org/fhir/StructureDefinition/string"
            ]
          }
        ],
        "constraint": [
          {
            "key": "email-format",
            "severity": "error",
            "human": "email format",
            "expression": "^\\S+@\\S+\\.\\S+$"
          }
        ]
      }
    ]
  }
}