def param_check(request):
    """
    Check that required parameters were passed.

    Args:
        request(rest_framework.request.Request): GET request with input parameters.

    Returns:
        dict: Dictionary with success or error key  and a message.
    """
    if request.method != "GET":
        return {"error": "only GET requests are allowed."}
    elif not request.GET.get("geometry", None):
        return {"error": "'geometry' is a required parameter."}
    elif not request.GET.get("end_time", None):
        return {"error": "'end_time' (YYYYMMDD) is a required parameter."}
    else:
        return {"success": "required parameters provided."}