changed react and python server for Download

union.py

@@ -0,0 +1,26 @@
+# encoding: utf-8
+"""
+Marshmallow fields
+------------------
+
+Extension on the already available marshmallow fields
+"""
+from marshmallow import ValidationError, fields
+
+
+class UnionField(fields.Field):
+    """Field that deserializes multi-type input data to app-level objects."""
+    def __init__(self, types: list = [], *args, **kwargs) -> None:
+        super().__init__(*args, **kwargs)
+        if types:
+            self.types = types
+        else:
+            raise AttributeError('No types provided on union field')
+
+    def _deserialize(self, value, attr, data, **kwargs):
+        if bool([isinstance(value, i) for i in self.types if isinstance(value, i)]):
+            return value
+        else:
+            raise ValidationError(
+                f'Field shoud be any of the following types: [{", ".join([str(i) for i in self.types])}]'
+            )