diff --git a/Custom_Hooks/eb_hooks.py b/Custom_Hooks/eb_hooks.py
index 69112254ea7768531e8c8ed79efa3c02ce539015..530f02167ddc31e53e816da62e490b30fd31e639 100644
--- a/Custom_Hooks/eb_hooks.py
+++ b/Custom_Hooks/eb_hooks.py
@@ -320,7 +320,7 @@ def pre_ready_hook(self, *args, **kwargs):
     override_toolchain_check = os.getenv("JSC_OVERRIDE_TOOLCHAIN_CHECK")
     if not override_toolchain_check:
         toolchain_name = toolchain["name"]
-        if not toolchain_name in SUPPORTED_TOOLCHAIN_FAMILIES and os.getenv('USER') is not 'swmanage':
+        if not toolchain_name in SUPPORTED_TOOLCHAIN_FAMILIES and os.getenv('USER') not in 'swmanage':
             stage = os.getenv("STAGE", default=None)
             if stage:
                 # Clean things up if it is a Devel stage
@@ -365,7 +365,7 @@ def pre_ready_hook(self, *args, **kwargs):
     # overridden, only experts should know that)
     override_mpi_check = os.getenv("JSC_OVERRIDE_MPI_CHECK")
     if not override_mpi_check:
-        if is_mpi and GOLDEN_REPO not in path_to_ec and os.getenv('USER') is not 'swmanage':
+        if is_mpi and GOLDEN_REPO not in path_to_ec and os.getenv('USER') not in 'swmanage':
             print_warning(
                 "\nYou are attempting to install a non-system MPI implementation (%s), "
                 "this is very likely to lead to severe performance degradation. Please "