not sure if this is of any help:
(Pdb) self._globals
{'_iter_unpack_sequence_': <function guarded_iter_unpack_sequence at 0x109947938>,
'__metaclass__': <function _metaclass at 0x1099c0140>,
'sequence': <module 'DocumentTemplate.sequence' from '/Users/rolf/Plone52/buildout-cache/eggs/DocumentTemplate-3.1b2-py2.7.egg/DocumentTemplate/sequence/__init__.pyc'>,
'__builtins__': {'all': <function guarded_all at 0x1099c00c8>,
'BytesWarning': <type 'exceptions.BytesWarning'>,
'pow': <built-in function pow>,
'RuntimeError': <type 'exceptions.RuntimeError'>,
'float': <type 'float'>,
'MemoryError': <type 'exceptions.MemoryError'>,
'_getattr_': <function safer_getattr at 0x1099478c0>,
'DateTime': <class 'DateTime.DateTime.DateTime'>,
'StopIteration': <type 'exceptions.StopIteration'>,
'divmod': <built-in function divmod>,
'unicode': <type 'unicode'>,
'enumerate': <function guarded_enumerate at 0x1099bfb90>,
'apply': <function builtin_guarded_apply at 0x1099bff50>,
'isinstance': <built-in function isinstance>,
'same_type': <function same_type at 0x109947c08>,
'basestring': <type 'basestring'>,
'UnicodeError': <type 'exceptions.UnicodeError'>,
'zip': <function guarded_zip at 0x1099bfaa0>,
'LookupError': <type 'exceptions.LookupError'>,
'hex': <built-in function hex>,
'long': <type 'long'>,
'IndentationError': <type 'exceptions.IndentationError'>,
'NameError': <type 'exceptions.NameError'>,
'ImportError': <type 'exceptions.ImportError'>,
'chr': <built-in function chr>,
'complex': <type 'complex'>,
'dict': <AccessControl.ZopeGuards.GuardedDictType instance at 0x1099a76c8>,
'__import__': <function guarded_import at 0x1099bfb18>,
'IOError': <type 'exceptions.IOError'>,
'oct': <built-in function oct>,
'reorder': <function reorder at 0x1099652a8>,
'SystemExit': <type 'exceptions.SystemExit'>,
'Exception': <type 'exceptions.Exception'>,
'random': <module 'random' from '/usr/local/Cellar/python/2.7.13_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/random.pyc'>,
'string': <module 'string' from '/usr/local/Cellar/python/2.7.13_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/string.pyc'>,
'StandardError': <type 'exceptions.StandardError'>,
'tuple': <type 'tuple'>,
'reduce': <function guarded_reduce at 0x1099bf8c0>,
'repr': <built-in function repr>,
'next': <function guarded_next at 0x1099bf410>,
'UnicodeEncodeError': <type 'exceptions.UnicodeEncodeError'>,
'UnicodeDecodeError': <type 'exceptions.UnicodeDecodeError'>,
'hasattr': <function guarded_hasattr at 0x1099bf050>,
'delattr': <function guarded_delattr at 0x109947848>,
'IndexError': <type 'exceptions.IndexError'>,
'RuntimeWarning': <type 'exceptions.RuntimeWarning'>,
'setattr': <function guarded_setattr at 0x109947578>,
'list': <AccessControl.ZopeGuards.GuardedListType instance at 0x1099a7680>,
'SyntaxWarning': <type 'exceptions.SyntaxWarning'>,
'iter': <function guarded_iter at 0x1099bf758>,
'whrandom': <module 'random' from '/usr/local/Cellar/python/2.7.13_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/random.pyc'>,
'ArithmeticError': <type 'exceptions.ArithmeticError'>,
'Warning': <type 'exceptions.Warning'>,
'math': <module 'math' from '/Users/rolf/Plone52/zinstance/lib/python2.7/lib-dynload/math.so'>,
'str': <type 'str'>,
'round': <built-in function round>,
'cmp': <built-in function cmp>,
'False': False,
'GeneratorExit': <type 'exceptions.GeneratorExit'>,
'set': <type 'set'>,
'int': <type 'int'>,
'xrange': <type 'xrange'>,
'UnicodeTranslateError': <type 'exceptions.UnicodeTranslateError'>,
'KeyError': <type 'exceptions.KeyError'>,
'PendingDeprecationWarning': <type 'exceptions.PendingDeprecationWarning'>,
'issubclass': <built-in function issubclass>,
'EnvironmentError': <type 'exceptions.EnvironmentError'>,
'unichr': <built-in function unichr>,
'id': <built-in function id>,
'BufferError': <type 'exceptions.BufferError'>,
'slice': <type 'slice'>,
'DeprecationWarning': <type 'exceptions.DeprecationWarning'>,
'min': <function guarded_min at 0x1099bf9b0>,
'FloatingPointError': <type 'exceptions.FloatingPointError'>,
'UnicodeWarning': <type 'exceptions.UnicodeWarning'>,
'sum': <function guarded_sum at 0x1099bfde8>,
'AttributeError': <type 'exceptions.AttributeError'>,
'any': <function guarded_any at 0x1099c0050>,
'getattr': <built-in function guarded_getattr>,
'abs': <built-in function abs>,
'bool': <type 'bool'>,
'test': <function test at 0x10994d9b0>,
'True': True,
'ValueError': <type 'exceptions.ValueError'>,
'FutureWarning': <type 'exceptions.FutureWarning'>,
'ImportWarning': <type 'exceptions.ImportWarning'>,
'map': <function guarded_map at 0x1099bfa28>,
'None': None,
'hash': <built-in function hash>,
'max': <function guarded_max at 0x1099bf938>,
'len': <built-in function len>,
'TabError': <type 'exceptions.TabError'>,
'callable': <built-in function callable>,
'SyntaxError': <type 'exceptions.SyntaxError'>,
'OSError': <type 'exceptions.OSError'>,
'frozenset': <type 'frozenset'>,
'ord': <built-in function ord>,
'ReferenceError': <type 'exceptions.ReferenceError'>,
'AssertionError': <type 'exceptions.AssertionError'>,
'TypeError': <type 'exceptions.TypeError'>,
'KeyboardInterrupt': <type 'exceptions.KeyboardInterrupt'>,
'UserWarning': <type 'exceptions.UserWarning'>,
'ZeroDivisionError': <type 'exceptions.ZeroDivisionError'>,
'UnboundLocalError': <type 'exceptions.UnboundLocalError'>,
'filter': <function guarded_filter at 0x1099bf848>,
'range': <built-in function range>,
'EOFError': <type 'exceptions.EOFError'>,
'NotImplementedError': <type 'exceptions.NotImplementedError'>,
'SystemError': <type 'exceptions.SystemError'>,
'OverflowError': <type 'exceptions.OverflowError'>,
'BaseException': <type 'exceptions.BaseException'>},
'_apply_': <function guarded_apply at 0x1099bfed8>,
'_write_': <function guard at 0x109947500>,
'_print_': <class 'RestrictedPython.PrintCollector.PrintCollector'>,
'_getattr_': <built-in function guarded_getattr>,
'_inplacevar_': <function protected_inplacevar at 0x1099c0758>,
'_getiter_': <function guarded_iter at 0x1099bf758>,
'__debug__': True,
'_getitem_': <function guarded_getitem at 0x1099bf0c8>,
'_unpack_sequence_': <function guarded_unpack_sequence at 0x1099479b0>}
(Pdb) > /Users/rolf/Plone52/buildout-cache/eggs/Zope-4.1.1-py2.7.egg/Products/PageTemplates/ZRPythonExpr.py(47)__call__()