How to use the pydocstyle.__version__ function in pydocstyle

# The encoding of source files.
#source_encoding = 'utf-8-sig'

# The master toctree document.
master_doc = 'index'

# General information about the project.
project = 'pydocstyle'
copyright = '2016, Amir Rachum'

# The version info for the project you're documenting, acts as replacement for
# |version| and |release|, also used in various other places throughout the
# built documents.
#
# The short X.Y version.
version = pydocstyle.__version__
# The full version, including alpha/beta/rc tags.
release = pydocstyle.__version__

# The language for content autogenerated by Sphinx. Refer to documentation
# for a list of supported languages.
#language = None

# There are two options for replacing |today|: either, you set today to some
# non-false value, then it is used:
#today = ''
# Else, today_fmt is used as the format for a strftime call.
#today_fmt = '%B %d, %Y'

# List of patterns, relative to source directory, that match files and
# directories to ignore when looking for source files.
exclude_patterns = ['_build']

def tools_versions():
    """Return all lint tools versions."""
    return (
        ('pep8', pep8.__version__),
        ('flake8', flake8_version),
        ('pyflakes', pyflakes_version),
        ('mccabe', mccabe.__version__),
        ('pydocstyle', pydocstyle_version),
        ('naming', pep8ext_naming.__version__),
        ('debugger', flake8_debugger.__version__),
        ('import-order', flake8_import_order_version),
    )

# The master toctree document.
master_doc = 'index'

# General information about the project.
project = 'pydocstyle'
copyright = '2016, Amir Rachum'

# The version info for the project you're documenting, acts as replacement for
# |version| and |release|, also used in various other places throughout the
# built documents.
#
# The short X.Y version.
version = pydocstyle.__version__
# The full version, including alpha/beta/rc tags.
release = pydocstyle.__version__

# The language for content autogenerated by Sphinx. Refer to documentation
# for a list of supported languages.
#language = None

# There are two options for replacing |today|: either, you set today to some
# non-false value, then it is used:
#today = ''
# Else, today_fmt is used as the format for a strftime call.
#today_fmt = '%B %d, %Y'

# List of patterns, relative to source directory, that match files and
# directories to ignore when looking for source files.
exclude_patterns = ['_build']

# The reST default role (used for this markup: `text`) to use for all