Use custom StrEnum

curvesim/constants.py

@@ -1,7 +1,24 @@
 from enum import Enum
 
 
-class Chain(str, Enum):
+class StrEnum(str, Enum):
+    def __str__(self):
+        """
+        Regular Enum's __str__ is the name, rather than the value,
+        e.g.
+
+        >>> str(Chain.MAINNET)
+        'Chain.MAINNET'
+
+        so we need to explicit use the value.
+
+        This is not necessary in Python 3.11 or above, where the
+        builtin `StrEnum` has this behavior.
+        """
+        return str.__str__(self)
+
+
+class Chain(StrEnum):
     MAINNET = "mainnet"
     ARBITRUM = "arbitrum"
     OPTIMISM = "optimism"
@@ -11,6 +28,6 @@ class Chain(str, Enum):
     XDAI = "xdai"
 
 
-class Env(str, Enum):
+class Env(StrEnum):
     PROD = "prod"
     STAGING = "staging"