ENH: use sanitize_value helper instead of adhoc replacement of _

This seems to Closes #172 as well

dandischema/metadata.py

@@ -15,7 +15,7 @@
 )
 from .exceptions import JsonschemaValidationError, PydanticValidationError
 from . import models
-from .utils import _ensure_newline, version2tuple
+from .utils import _ensure_newline, sanitize_value, version2tuple
 
 schema_map = {
     "Dandiset": "dandiset.json",
@@ -255,7 +255,7 @@ def migrate(
 def _get_samples(value: dict, stats: _stats_type, hierarchy: Any) -> _stats_type:
     if "sampleType" in value:
         sampletype = value["sampleType"]["name"]
-        obj = value["identifier"].replace("_", "-")
+        obj = sanitize_value(value["identifier"])
         if obj not in stats[sampletype]:
             stats[sampletype].append(obj)
     if "wasDerivedFrom" in value:
@@ -299,7 +299,7 @@ def _add_asset_to_stats(assetmeta: Dict[str, Any], stats: _stats_type) -> None:
                 if value["species"] not in stats["species"]:
                     stats["species"].append(value["species"])
             if value.get("identifier", None):
-                subject = value["identifier"].replace("_", "-")
+                subject = sanitize_value(value["identifier"])
                 if subject not in stats["subjects"]:
                     stats["subjects"].append(subject)