text: """I'm pasting here a copy of Python's 3.7.2 LICENSE since I used some parts of
  the asyncio and asyncio.sslproto code to provide the necessary functionality
  to other versions of Python.
  
  
  A. HISTORY OF THE SOFTWARE
  ==========================
  
  Python was created in the early 1990s by Guido van Rossum at Stichting
  Mathematisch Centrum (CWI, see http://www.cwi.nl) in the Netherlands
  as a successor of a language called ABC.  Guido remains Python's
  principal author, although it includes many contributions from others.
  
  In 1995, Guido continued his work on Python at the Corporation for
  National Research Initiatives (CNRI, see http://www.cnri.reston.va.us)
  in Reston, Virginia where he released several versions of the
  software.
  
  In May 2000, Guido and the Python core development team moved to
  BeOpen.com to form the BeOpen PythonLabs team.  In October of the same
  year, the PythonLabs team moved to Digital Creations, which became
  Zope Corporation.  In 2001, the Python Software Foundation (PSF, see
  https://www.python.org/psf/) was formed, a non-profit organization
  created specifically to own Python-related Intellectual Property.
  Zope Corporation was a sponsoring member of the PSF.
  
  All Python releases are Open Source (see http://www.opensource.org for
  the Open Source Definition).  Historically, most, but not all, Python
  releases have also been GPL-compatible; the table below summarizes
  the various releases.
  
      Release         Derived     Year        Owner       GPL-
                      from                                compatible? (1)
  
      0.9.0 thru 1.2              1991-1995   CWI         yes
      1.3 thru 1.5.2  1.2         1995-1999   CNRI        yes
      1.6             1.5.2       2000        CNRI        no
      2.0             1.6         2000        BeOpen.com  no
      1.6.1           1.6         2001        CNRI        yes (2)
      2.1             2.0+1.6.1   2001        PSF         no
      2.0.1           2.0+1.6.1   2001        PSF         yes
      2.1.1           2.1+2.0.1   2001        PSF         yes
      2.1.2           2.1.1       2002        PSF         yes
      2.1.3           2.1.2       2002        PSF         yes
      2.2 and above   2.1.1       2001-now    PSF         yes
  
  Footnotes:
  
  (1) GPL-compatible doesn't mean that we're distributing Python under
      the GPL.  All Python licenses, unlike the GPL, let you distribute
      a modified version without making your changes open source.  The
      GPL-compatible licenses make it possible to combine Python with
      other software that is released under the GPL; the others don't.
  
  (2) According to Richard Stallman, 1.6.1 is not GPL-compatible,
      because its license has a choice of law clause.  According to
      CNRI, however, Stallman's lawyer has told CNRI's lawyer that 1.6.1
      is "not incompatible" with the GPL.
  
  Thanks to the many outside volunteers who have worked under Guido's
  direction to make these releases possible.
  
  
  B. TERMS AND CONDITIONS FOR ACCESSING OR OTHERWISE USING PYTHON
  ===============================================================
  
  PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
  --------------------------------------------
  
  1. This LICENSE AGREEMENT is between the Python Software Foundation
  ("PSF"), and the Individual or Organization ("Licensee") accessing and
  otherwise using this software ("Python") in source or binary form and
  its associated documentation.
  
  2. Subject to the terms and conditions of this License Agreement, PSF hereby
  grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
  analyze, test, perform and/or display publicly, prepare derivative works,
  distribute, and otherwise use Python alone or in any derivative version,
  provided, however, that PSF's License Agreement and PSF's notice of copyright,
  i.e., "Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
  2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software Foundation; All
  Rights Reserved" are retained in Python alone or in any derivative version
  prepared by Licensee.
  
  3. In the event Licensee prepares a derivative work that is based on
  or incorporates Python or any part thereof, and wants to make
  the derivative work available to others as provided herein, then
  Licensee hereby agrees to include in any such work a brief summary of
  the changes made to Python.
  
  4. PSF is making Python available to Licensee on an "AS IS"
  basis.  PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
  IMPLIED.  BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND
  DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
  FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT
  INFRINGE ANY THIRD PARTY RIGHTS.
  
  5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
  FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS
  A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,
  OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
  
  6. This License Agreement will automatically terminate upon a material
  breach of its terms and conditions.
  
  7. Nothing in this License Agreement shall be deemed to create any
  relationship of agency, partnership, or joint venture between PSF and
  Licensee.  This License Agreement does not grant permission to use PSF
  trademarks or trade name in a trademark sense to endorse or promote
  products or services of Licensee, or any third party.
  
  8. By copying, installing or otherwise using Python, Licensee
  agrees to be bound by the terms and conditions of this License
  Agreement.
  
  
  BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0
  -------------------------------------------
  
  BEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1
  
  1. This LICENSE AGREEMENT is between BeOpen.com ("BeOpen"), having an
  office at 160 Saratoga Avenue, Santa Clara, CA 95051, and the
  Individual or Organization ("Licensee") accessing and otherwise using
  this software in source or binary form and its associated
  documentation ("the Software").
  
  2. Subject to the terms and conditions of this BeOpen Python License
  Agreement, BeOpen hereby grants Licensee a non-exclusive,
  royalty-free, world-wide license to reproduce, analyze, test, perform
  and/or display publicly, prepare derivative works, distribute, and
  otherwise use the Software alone or in any derivative version,
  provided, however, that the BeOpen Python License is retained in the
  Software, alone or in any derivative version prepared by Licensee.
  
  3. BeOpen is making the Software available to Licensee on an "AS IS"
  basis.  BEOPEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
  IMPLIED.  BY WAY OF EXAMPLE, BUT NOT LIMITATION, BEOPEN MAKES NO AND
  DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
  FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE SOFTWARE WILL NOT
  INFRINGE ANY THIRD PARTY RIGHTS.
  
  4. BEOPEN SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THE
  SOFTWARE FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS
  AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THE SOFTWARE, OR ANY
  DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
  
  5. This License Agreement will automatically terminate upon a material
  breach of its terms and conditions.
  
  6. This License Agreement shall be governed by and interpreted in all
  respects by the law of the State of California, excluding conflict of
  law provisions.  Nothing in this License Agreement shall be deemed to
  create any relationship of agency, partnership, or joint venture
  between BeOpen and Licensee.  This License Agreement does not grant
  permission to use BeOpen trademarks or trade names in a trademark
  sense to endorse or promote products or services of Licensee, or any
  third party.  As an exception, the "BeOpen Python" logos available at
  http://www.pythonlabs.com/logos.html may be used according to the
  permissions granted on that web page.
  
  7. By copying, installing or otherwise using the software, Licensee
  agrees to be bound by the terms and conditions of this License
  Agreement.
  
  
  CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1
  ---------------------------------------
  
  1. This LICENSE AGREEMENT is between the Corporation for National
  Research Initiatives, having an office at 1895 Preston White Drive,
  Reston, VA 20191 ("CNRI"), and the Individual or Organization
  ("Licensee") accessing and otherwise using Python 1.6.1 software in
  source or binary form and its associated documentation.
  
  2. Subject to the terms and conditions of this License Agreement, CNRI
  hereby grants Licensee a nonexclusive, royalty-free, world-wide
  license to reproduce, analyze, test, perform and/or display publicly,
  prepare derivative works, distribute, and otherwise use Python 1.6.1
  alone or in any derivative version, provided, however, that CNRI's
  License Agreement and CNRI's notice of copyright, i.e., "Copyright (c)
  1995-2001 Corporation for National Research Initiatives; All Rights
  Reserved" are retained in Python 1.6.1 alone or in any derivative
  version prepared by Licensee.  Alternately, in lieu of CNRI's License
  Agreement, Licensee may substitute the following text (omitting the
  quotes): "Python 1.6.1 is made available subject to the terms and
  conditions in CNRI's License Agreement.  This Agreement together with
  Python 1.6.1 may be located on the Internet using the following
  unique, persistent identifier (known as a handle): 1895.22/1013.  This
  Agreement may also be obtained from a proxy server on the Internet
  using the following URL: http://hdl.handle.net/1895.22/1013".
  
  3. In the event Licensee prepares a derivative work that is based on
  or incorporates Python 1.6.1 or any part thereof, and wants to make
  the derivative work available to others as provided herein, then
  Licensee hereby agrees to include in any such work a brief summary of
  the changes made to Python 1.6.1.
  
  4. CNRI is making Python 1.6.1 available to Licensee on an "AS IS"
  basis.  CNRI MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
  IMPLIED.  BY WAY OF EXAMPLE, BUT NOT LIMITATION, CNRI MAKES NO AND
  DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
  FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON 1.6.1 WILL NOT
  INFRINGE ANY THIRD PARTY RIGHTS.
  
  5. CNRI SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
  1.6.1 FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS
  A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 1.6.1,
  OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
  
  6. This License Agreement will automatically terminate upon a material
  breach of its terms and conditions.
  
  7. This License Agreement shall be governed by the federal
  intellectual property law of the United States, including without
  limitation the federal copyright law, and, to the extent such
  U.S. federal law does not apply, by the law of the Commonwealth of
  Virginia, excluding Virginia's conflict of law provisions.
  Notwithstanding the foregoing, with regard to derivative works based
  on Python 1.6.1 that incorporate non-separable material that was
  previously distributed under the GNU General Public License (GPL), the
  law of the Commonwealth of Virginia shall govern this License
  Agreement only as to issues arising under or with respect to
  Paragraphs 4, 5, and 7 of this License Agreement.  Nothing in this
  License Agreement shall be deemed to create any relationship of
  agency, partnership, or joint venture between CNRI and Licensee.  This
  License Agreement does not grant permission to use CNRI trademarks or
  trade name in a trademark sense to endorse or promote products or
  services of Licensee, or any third party.
  
  8. By clicking on the "ACCEPT" button where indicated, or by copying,
  installing or otherwise using Python 1.6.1, Licensee agrees to be
  bound by the terms and conditions of this License Agreement.
  
          ACCEPT
  
  
  CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2
  --------------------------------------------------
  
  Copyright (c) 1991 - 1995, Stichting Mathematisch Centrum Amsterdam,
  The Netherlands.  All rights reserved.
  
  Permission to use, copy, modify, and distribute this software and its
  documentation for any purpose and without fee is hereby granted,
  provided that the above copyright notice appear in all copies and that
  both that copyright notice and this permission notice appear in
  supporting documentation, and that the name of Stichting Mathematisch
  Centrum or CWI not be used in advertising or publicity pertaining to
  distribution of the software without specific, written prior
  permission.
  
  STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
  THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
  FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  """
  
  import asyncio
  import os
  import sys
  import warnings
  
  from asyncio import sslproto
  from asyncio.selector_events import (
      BaseSelectorEventLoop,
      _SelectorSocketTransport,
  )
  from asyncio.proactor_events import (
      BaseProactorEventLoop,
      _ProactorSocketTransport,
  )
  
  if sys.version_info[:2] > (3, 6):
      warnings.warn(
          "The 'SSLProtocolBackportLoopPolicy' is not needed in Python version "
          "3.7 onwards",
          ImportWarning
      )
  
  _policy = asyncio.get_event_loop_policy().__class__
  _loop_factory = _policy._loop_factory
  
  if issubclass(_loop_factory, BaseSelectorEventLoop):
      _socket_transport = _SelectorSocketTransport  # posix
  elif issubclass(_loop_factory, BaseProactorEventLoop):  # noqa how to test this?
      _socket_transport = _ProactorSocketTransport  # windows
  
  
  def _get_ssl_handshake_timeout():
      _ssl_handshake_timeout = os.getenv("PYSSLPROTO37_HANDSHAKE_TIMEOUT")
      if _ssl_handshake_timeout is None:
          _ssl_handshake_timeout = 60.0
      else:
          # no try / except, simply throw the error
          _ssl_handshake_timeout = float(_ssl_handshake_timeout)
      return _ssl_handshake_timeout
  
  
  class SSLProtocolBackport(sslproto.SSLProtocol):
      def __init__(
          self,
          loop,
          app_protocol,
          sslcontext,
          waiter,
          server_side=False,
          server_hostname=None,
          call_connection_made=True,
          ssl_handshake_timeout=None
      ):
          super().__init__(
              loop,
              app_protocol,
              sslcontext,
              waiter,
              server_side=server_side,
              server_hostname=server_hostname,
              call_connection_made=call_connection_made
          )
          if ssl_handshake_timeout is None:
              ssl_handshake_timeout = _get_ssl_handshake_timeout()
          elif ssl_handshake_timeout <= 0:
              raise ValueError(
                  "ssl_handshake_timeout should be a positive number, "
                  "got {}".format(ssl_handshake_timeout))
          self._ssl_handshake_timeout = ssl_handshake_timeout
  
      def _start_handshake(self):
          super()._start_handshake()
          self._handshake_timeout_handle = self._loop.call_later(
              self._ssl_handshake_timeout, self._check_handshake_timeout
          )
  
      def _check_handshake_timeout(self):
          if self._in_handshake is True:  # this is always be true (IMO)
              msg = (
                  "SSL handshake is taking longer than "
                  "{ssl_handshake_timeout} seconds: "
                  "aborting the connection".format(
                      ssl_handshake_timeout=self._ssl_handshake_timeout
                  )
              )
              self._fatal_error(ConnectionAbortedError(msg))
  
      def _on_handshake_complete(self, handshake_exc):
          self._handshake_timeout_handle.cancel()
          super()._on_handshake_complete(handshake_exc)
  
  
  class SSLProtocolBackportEventLoop(_loop_factory):
      def _make_ssl_transport(
          self,
          rawsock,
          protocol,
          sslcontext,
          waiter=None,
          *,
          server_side=False,
          server_hostname=None,
          extra=None,
          server=None,
          ssl_handshake_timeout=None
      ):
          if not sslproto._is_sslproto_available():  # noqa how to test this?
              if _socket_transport is _ProactorSocketTransport:
                  raise NotImplementedError(
                      "Proactor event loop requires Python 3.5"
                      " or newer (ssl.MemoryBIO) to support SSL"
                  )
              return self._make_legacy_ssl_transport(
                  rawsock,
                  protocol,
                  sslcontext,
                  waiter,
                  server_side=server_side,
                  server_hostname=server_hostname,
                  extra=extra,
                  server=server
              )
  
          ssl_protocol = SSLProtocolBackport(
              self,
              protocol,
              sslcontext,
              waiter,
              server_side,
              server_hostname,
              ssl_handshake_timeout=ssl_handshake_timeout
          )
          _socket_transport(
              self, rawsock, ssl_protocol, extra=extra, server=server
          )
          return ssl_protocol._app_transport
  
  
  class SSLProtocolBackportLoopPolicy(_policy):
      _loop_factory = SSLProtocolBackportEventLoop
  
  
  __all__ = [
      "SSLProtocolBackportLoopPolicy",
      "SSLProtocolBackportEventLoop",
      "SSLProtocolBackport"
  ]
  