--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.7/site-packages/boltons/namedutils.py	Sat May 02 07:14:21 2020 -0400
@@ -0,0 +1,369 @@
+# -*- coding: utf-8 -*-
+"""\
+The ``namedutils`` module defines two lightweight container types:
+:class:`namedtuple` and :class:`namedlist`. Both are subtypes of built-in
+sequence types, which are very fast and efficient. They simply add
+named attribute accessors for specific indexes within themselves.
+
+The :class:`namedtuple` is identical to the built-in
+:class:`collections.namedtuple`, with a couple of enhancements,
+including a ``__repr__`` more suitable to inheritance.
+
+The :class:`namedlist` is the mutable counterpart to the
+:class:`namedtuple`, and is much faster and lighter-weight than
+full-blown :class:`object`. Consider this if you're implementing nodes
+in a tree, graph, or other mutable data structure. If you want an even
+skinnier approach, you'll probably have to look to C.
+"""
+
+from __future__ import print_function
+
+import sys as _sys
+try:
+    from collections import OrderedDict
+except ImportError:
+    # backwards compatibility (2.6 has no OrderedDict)
+    OrderedDict = dict
+from keyword import iskeyword as _iskeyword
+from operator import itemgetter as _itemgetter
+
+try:
+    basestring
+    def exec_(code, global_env):
+        exec("exec code in global_env")
+except NameError:
+    basestring = (str, bytes)  # Python 3 compat
+    def exec_(code, global_env):
+        exec(code, global_env)
+
+__all__ = ['namedlist', 'namedtuple']
+
+# Tiny templates
+
+_repr_tmpl = '{name}=%r'
+
+_imm_field_tmpl = '''\
+    {name} = _property(_itemgetter({index:d}), doc='Alias for field {index:d}')
+'''
+
+_m_field_tmpl = '''\
+    {name} = _property(_itemgetter({index:d}), _itemsetter({index:d}), doc='Alias for field {index:d}')
+'''
+
+#################################################################
+### namedtuple
+#################################################################
+
+_namedtuple_tmpl = '''\
+class {typename}(tuple):
+    '{typename}({arg_list})'
+
+    __slots__ = ()
+
+    _fields = {field_names!r}
+
+    def __new__(_cls, {arg_list}):  # TODO: tweak sig to make more extensible
+        'Create new instance of {typename}({arg_list})'
+        return _tuple.__new__(_cls, ({arg_list}))
+
+    @classmethod
+    def _make(cls, iterable, new=_tuple.__new__, len=len):
+        'Make a new {typename} object from a sequence or iterable'
+        result = new(cls, iterable)
+        if len(result) != {num_fields:d}:
+            raise TypeError('Expected {num_fields:d}'
+                            ' arguments, got %d' % len(result))
+        return result
+
+    def __repr__(self):
+        'Return a nicely formatted representation string'
+        tmpl = self.__class__.__name__ + '({repr_fmt})'
+        return tmpl % self
+
+    def _asdict(self):
+        'Return a new OrderedDict which maps field names to their values'
+        return OrderedDict(zip(self._fields, self))
+
+    def _replace(_self, **kwds):
+        'Return a new {typename} object replacing field(s) with new values'
+        result = _self._make(map(kwds.pop, {field_names!r}, _self))
+        if kwds:
+            raise ValueError('Got unexpected field names: %r' % kwds.keys())
+        return result
+
+    def __getnewargs__(self):
+        'Return self as a plain tuple.  Used by copy and pickle.'
+        return tuple(self)
+
+    __dict__ = _property(_asdict)
+
+    def __getstate__(self):
+        'Exclude the OrderedDict from pickling'  # wat
+        pass
+
+{field_defs}
+'''
+
+def namedtuple(typename, field_names, verbose=False, rename=False):
+    """Returns a new subclass of tuple with named fields.
+
+    >>> Point = namedtuple('Point', ['x', 'y'])
+    >>> Point.__doc__                   # docstring for the new class
+    'Point(x, y)'
+    >>> p = Point(11, y=22)             # instantiate with pos args or keywords
+    >>> p[0] + p[1]                     # indexable like a plain tuple
+    33
+    >>> x, y = p                        # unpack like a regular tuple
+    >>> x, y
+    (11, 22)
+    >>> p.x + p.y                       # fields also accessible by name
+    33
+    >>> d = p._asdict()                 # convert to a dictionary
+    >>> d['x']
+    11
+    >>> Point(**d)                      # convert from a dictionary
+    Point(x=11, y=22)
+    >>> p._replace(x=100)               # _replace() is like str.replace() but targets named fields
+    Point(x=100, y=22)
+    """
+
+    # Validate the field names.  At the user's option, either generate an error
+    # message or automatically replace the field name with a valid name.
+    if isinstance(field_names, basestring):
+        field_names = field_names.replace(',', ' ').split()
+    field_names = [str(x) for x in field_names]
+    if rename:
+        seen = set()
+        for index, name in enumerate(field_names):
+            if (not all(c.isalnum() or c == '_' for c in name)
+                or _iskeyword(name)
+                or not name
+                or name[0].isdigit()
+                or name.startswith('_')
+                or name in seen):
+                field_names[index] = '_%d' % index
+            seen.add(name)
+    for name in [typename] + field_names:
+        if not all(c.isalnum() or c == '_' for c in name):
+            raise ValueError('Type names and field names can only contain '
+                             'alphanumeric characters and underscores: %r'
+                             % name)
+        if _iskeyword(name):
+            raise ValueError('Type names and field names cannot be a '
+                             'keyword: %r' % name)
+        if name[0].isdigit():
+            raise ValueError('Type names and field names cannot start with '
+                             'a number: %r' % name)
+    seen = set()
+    for name in field_names:
+        if name.startswith('_') and not rename:
+            raise ValueError('Field names cannot start with an underscore: '
+                             '%r' % name)
+        if name in seen:
+            raise ValueError('Encountered duplicate field name: %r' % name)
+        seen.add(name)
+
+    # Fill-in the class template
+    fmt_kw = {'typename': typename}
+    fmt_kw['field_names'] = tuple(field_names)
+    fmt_kw['num_fields'] = len(field_names)
+    fmt_kw['arg_list'] = repr(tuple(field_names)).replace("'", "")[1:-1]
+    fmt_kw['repr_fmt'] = ', '.join(_repr_tmpl.format(name=name)
+                                   for name in field_names)
+    fmt_kw['field_defs'] = '\n'.join(_imm_field_tmpl.format(index=index, name=name)
+                                     for index, name in enumerate(field_names))
+    class_definition = _namedtuple_tmpl.format(**fmt_kw)
+
+    if verbose:
+        print(class_definition)
+
+    # Execute the template string in a temporary namespace and support
+    # tracing utilities by setting a value for frame.f_globals['__name__']
+    namespace = dict(_itemgetter=_itemgetter,
+                     __name__='namedtuple_%s' % typename,
+                     OrderedDict=OrderedDict,
+                     _property=property,
+                     _tuple=tuple)
+    try:
+        exec_(class_definition, namespace)
+    except SyntaxError as e:
+        raise SyntaxError(e.message + ':\n' + class_definition)
+    result = namespace[typename]
+
+    # For pickling to work, the __module__ variable needs to be set to the frame
+    # where the named tuple is created.  Bypass this step in environments where
+    # sys._getframe is not defined (Jython for example) or sys._getframe is not
+    # defined for arguments greater than 0 (IronPython).
+    try:
+        frame = _sys._getframe(1)
+        result.__module__ = frame.f_globals.get('__name__', '__main__')
+    except (AttributeError, ValueError):
+        pass
+
+    return result
+
+
+#################################################################
+### namedlist
+#################################################################
+
+_namedlist_tmpl = '''\
+class {typename}(list):
+    '{typename}({arg_list})'
+
+    __slots__ = ()
+
+    _fields = {field_names!r}
+
+    def __new__(_cls, {arg_list}):  # TODO: tweak sig to make more extensible
+        'Create new instance of {typename}({arg_list})'
+        return _list.__new__(_cls, ({arg_list}))
+
+    def __init__(self, {arg_list}):  # tuple didn't need this but list does
+        return _list.__init__(self, ({arg_list}))
+
+    @classmethod
+    def _make(cls, iterable, new=_list, len=len):
+        'Make a new {typename} object from a sequence or iterable'
+        # why did this function exist? why not just star the
+        # iterable like below?
+        result = cls(*iterable)
+        if len(result) != {num_fields:d}:
+            raise TypeError('Expected {num_fields:d} arguments,'
+                            ' got %d' % len(result))
+        return result
+
+    def __repr__(self):
+        'Return a nicely formatted representation string'
+        tmpl = self.__class__.__name__ + '({repr_fmt})'
+        return tmpl % tuple(self)
+
+    def _asdict(self):
+        'Return a new OrderedDict which maps field names to their values'
+        return OrderedDict(zip(self._fields, self))
+
+    def _replace(_self, **kwds):
+        'Return a new {typename} object replacing field(s) with new values'
+        result = _self._make(map(kwds.pop, {field_names!r}, _self))
+        if kwds:
+            raise ValueError('Got unexpected field names: %r' % kwds.keys())
+        return result
+
+    def __getnewargs__(self):
+        'Return self as a plain list.  Used by copy and pickle.'
+        return tuple(self)
+
+    __dict__ = _property(_asdict)
+
+    def __getstate__(self):
+        'Exclude the OrderedDict from pickling'  # wat
+        pass
+
+{field_defs}
+'''
+
+
+def namedlist(typename, field_names, verbose=False, rename=False):
+    """Returns a new subclass of list with named fields.
+
+    >>> Point = namedlist('Point', ['x', 'y'])
+    >>> Point.__doc__                   # docstring for the new class
+    'Point(x, y)'
+    >>> p = Point(11, y=22)             # instantiate with pos args or keywords
+    >>> p[0] + p[1]                     # indexable like a plain list
+    33
+    >>> x, y = p                        # unpack like a regular list
+    >>> x, y
+    (11, 22)
+    >>> p.x + p.y                       # fields also accessible by name
+    33
+    >>> d = p._asdict()                 # convert to a dictionary
+    >>> d['x']
+    11
+    >>> Point(**d)                      # convert from a dictionary
+    Point(x=11, y=22)
+    >>> p._replace(x=100)               # _replace() is like str.replace() but targets named fields
+    Point(x=100, y=22)
+    """
+
+    # Validate the field names.  At the user's option, either generate an error
+    # message or automatically replace the field name with a valid name.
+    if isinstance(field_names, basestring):
+        field_names = field_names.replace(',', ' ').split()
+    field_names = [str(x) for x in field_names]
+    if rename:
+        seen = set()
+        for index, name in enumerate(field_names):
+            if (not all(c.isalnum() or c == '_' for c in name)
+                or _iskeyword(name)
+                or not name
+                or name[0].isdigit()
+                or name.startswith('_')
+                or name in seen):
+                field_names[index] = '_%d' % index
+            seen.add(name)
+    for name in [typename] + field_names:
+        if not all(c.isalnum() or c == '_' for c in name):
+            raise ValueError('Type names and field names can only contain '
+                             'alphanumeric characters and underscores: %r'
+                             % name)
+        if _iskeyword(name):
+            raise ValueError('Type names and field names cannot be a '
+                             'keyword: %r' % name)
+        if name[0].isdigit():
+            raise ValueError('Type names and field names cannot start with '
+                             'a number: %r' % name)
+    seen = set()
+    for name in field_names:
+        if name.startswith('_') and not rename:
+            raise ValueError('Field names cannot start with an underscore: '
+                             '%r' % name)
+        if name in seen:
+            raise ValueError('Encountered duplicate field name: %r' % name)
+        seen.add(name)
+
+    # Fill-in the class template
+    fmt_kw = {'typename': typename}
+    fmt_kw['field_names'] = tuple(field_names)
+    fmt_kw['num_fields'] = len(field_names)
+    fmt_kw['arg_list'] = repr(tuple(field_names)).replace("'", "")[1:-1]
+    fmt_kw['repr_fmt'] = ', '.join(_repr_tmpl.format(name=name)
+                                   for name in field_names)
+    fmt_kw['field_defs'] = '\n'.join(_m_field_tmpl.format(index=index, name=name)
+                                     for index, name in enumerate(field_names))
+    class_definition = _namedlist_tmpl.format(**fmt_kw)
+
+    if verbose:
+        print(class_definition)
+
+    def _itemsetter(key):
+        def _itemsetter(obj, value):
+            obj[key] = value
+        return _itemsetter
+
+    # Execute the template string in a temporary namespace and support
+    # tracing utilities by setting a value for frame.f_globals['__name__']
+    namespace = dict(_itemgetter=_itemgetter,
+                     _itemsetter=_itemsetter,
+                     __name__='namedlist_%s' % typename,
+                     OrderedDict=OrderedDict,
+                     _property=property,
+                     _list=list)
+    try:
+        exec_(class_definition, namespace)
+    except SyntaxError as e:
+        raise SyntaxError(e.message + ':\n' + class_definition)
+    result = namespace[typename]
+
+    # For pickling to work, the __module__ variable needs to be set to
+    # the frame where the named list is created.  Bypass this step in
+    # environments where sys._getframe is not defined (Jython for
+    # example) or sys._getframe is not defined for arguments greater
+    # than 0 (IronPython).
+    try:
+        frame = _sys._getframe(1)
+        result.__module__ = frame.f_globals.get('__name__', '__main__')
+    except (AttributeError, ValueError):
+        pass
+
+    return result