diff --git a/planet/specs.py b/planet/specs.py
index 0f8c155..9c08a0b 100644
--- a/planet/specs.py
+++ b/planet/specs.py
@@ -15,7 +15,7 @@
 """Functionality for validating against the Planet API specification."""
 import json
 import logging
-
+import itertools
 from .constants import DATA_DIR
 
 PRODUCT_BUNDLE_SPEC_NAME = 'orders_product_bundle_2022_02_02.json'
@@ -37,19 +37,32 @@ SUPPORTED_FILE_FORMATS = ['COG', 'PL_NITF']
 LOGGER = logging.getLogger(__name__)
 
 
-class SpecificationException(Exception):
+class NoMatchException(Exception):
     '''No match was found'''
     pass
 
 
+class SpecificationException(Exception):
+    '''No match was found'''
+
+    def __init__(self, value, supported, field_name):
+        self.value = value
+        self.supported = supported
+        self.field_name = field_name
+        self.opts = ', '.join(["'" + s + "'" for s in supported])
+
+    def __str__(self):
+        return f'{self.field_name} - \'{self.value}\' is not one of {self.opts}.'
+
+
 def validate_bundle(bundle):
     supported = get_product_bundles()
     return _validate_field(bundle, supported, 'product_bundle')
 
 
 def validate_item_type(item_type, bundle):
-    bundle = validate_bundle(bundle)
-    supported = get_item_types(bundle)
+    validated_bundle = validate_bundle(bundle)
+    supported = get_item_types(validated_bundle)
     return _validate_field(item_type, supported, 'item_type')
 
 
@@ -73,20 +86,13 @@ def validate_file_format(file_format):
 
 def _validate_field(value, supported, field_name):
     try:
-        value = get_match(value, supported)
+        value = get_match(value, supported, field_name)
     except (NoMatchException):
-        opts = ', '.join(["'" + s + "'" for s in supported])
-        msg = f'{field_name} - \'{value}\' is not one of {opts}.'
-        raise SpecificationException(msg)
+        raise SpecificationException(value, supported, field_name)
     return value
 
 
-class NoMatchException(Exception):
-    '''No match was found'''
-    pass
-
-
-def get_match(test_entry, spec_entries):
+def get_match(test_entry, spec_entries, field_name):
     '''Find and return matching spec entry regardless of capitalization.
 
     This is helpful for working with the API spec, where the capitalization
@@ -96,7 +102,7 @@ def get_match(test_entry, spec_entries):
         match = next(e for e in spec_entries
                      if e.lower() == test_entry.lower())
     except (StopIteration):
-        raise NoMatchException('{test_entry} should be one of {spec_entries}')
+        raise SpecificationException(test_entry, spec_entries, field_name)
 
     return match
 
@@ -111,14 +117,15 @@ def get_item_types(product_bundle=None):
     '''If given product bundle, get specific item types supported by Orders
     API. Otherwise, get all item types supported by Orders API.'''
     spec = _get_product_bundle_spec()
+
     if product_bundle:
-        item_types = spec['bundles'][product_bundle]['assets'].keys()
+        item_types = set(spec['bundles'][product_bundle]['assets'].keys())
     else:
-        product_bundle = get_product_bundles()
-        all_item_types = []
-        for bundle in product_bundle:
-            all_item_types += [*spec['bundles'][bundle]['assets'].keys()]
-        item_types = set(all_item_types)
+        item_types = set(
+            itertools.chain.from_iterable(
+                spec['bundles'][bundle]['assets'].keys()
+                for bundle in get_product_bundles()))
+
     return item_types
 
 

diff --git a/tests/unit/test_specs.py b/tests/unit/test_specs.py
index 21b4e57..e7c17bf 100644
--- a/tests/unit/test_specs.py
+++ b/tests/unit/test_specs.py
@@ -46,10 +46,11 @@ def test_get_type_match():
     spec_list = ['Locket', 'drop', 'DEER']
 
     test_entry = 'locket'
-    assert 'Locket' == specs.get_match(test_entry, spec_list)
+    field_name = 'field_name'
+    assert 'Locket' == specs.get_match(test_entry, spec_list, field_name)
 
-    with pytest.raises(specs.NoMatchException):
-        specs.get_match('a', ['b'])
+    with pytest.raises(specs.SpecificationException):
+        specs.get_match('a', ['b'], field_name)
 
 
 def test_validate_bundle_supported():

planet order request: be more helpful on what bundles are available for a given item_type
Right now `planet order request` fails if item_type and bundle are incompatible by saying what item-types are compatible with the specified bundle. It would be more helpful to switch this so that it indicates what bundles are compatible with an item-type.

This has been hitting me as I've changed over from `PSScene4Band` to `PSScene` item-type, which is not compatible with the `analytic` bundle.
tests/unit/test_specs.py::test_get_type_match
tests/unit/test_specs.py::test_validate_bundle_supported tests/unit/test_specs.py::test_validate_bundle_notsupported tests/unit/test_specs.py::test_validate_item_type_supported tests/unit/test_specs.py::test_validate_item_type_notsupported_bundle tests/unit/test_specs.py::test_validate_item_type_notsupported_itemtype tests/unit/test_specs.py::test_validate_order_type_supported tests/unit/test_specs.py::test_validate_order_type_notsupported tests/unit/test_specs.py::test_validate_arhive_type_supported tests/unit/test_specs.py::test_validate_arhive_type_notsupported tests/unit/test_specs.py::test_validate_file_format_supported tests/unit/test_specs.py::test_validate_file_format_notsupported tests/unit/test_specs.py::test_get_product_bundles tests/unit/test_specs.py::test_get_item_types_with_bundle tests/unit/test_specs.py::test_get_item_types_without_bundle