How to use the pep8.register_check function in pep8

def _register_extensions():
    """Register all the extensions."""
    extensions = util.OrderedSet()
    extensions.add(('pep8', pep8.__version__))
    parser_hooks = []
    options_hooks = []
    ignored_hooks = []
    try:
        from pkg_resources import iter_entry_points
    except ImportError:
        pass
    else:
        for entry in iter_entry_points('flake8.extension'):
            # Do not verify that the requirements versions are valid
            checker = _load_entry_point(entry, verify_requirements=False)
            pep8.register_check(checker, codes=[entry.name])
            extensions.add((checker.name, checker.version))
            if hasattr(checker, 'add_options'):
                parser_hooks.append(checker.add_options)
            if hasattr(checker, 'parse_options'):
                options_hooks.append(checker.parse_options)
            if getattr(checker, 'off_by_default', False) is True:
                ignored_hooks.append(entry.name)
    return extensions, parser_hooks, options_hooks, ignored_hooks

def _register_extensions():
    """Register all the extensions."""
    extensions = OrderedSet()
    extensions.add(('pep8', pep8.__version__))
    parser_hooks = []
    options_hooks = []
    try:
        from pkg_resources import iter_entry_points
    except ImportError:
        pass
    else:
        for entry in iter_entry_points('flake8.extension'):
            checker = entry.load()
            pep8.register_check(checker, codes=[entry.name])
            extensions.add((checker.name, checker.version))
            if hasattr(checker, 'add_options'):
                parser_hooks.append(checker.add_options)
            if hasattr(checker, 'parse_options'):
                options_hooks.append(checker.parse_options)
    return extensions, parser_hooks, options_hooks

def main(paths=["."]):
    pep8.register_check(checkNames)
    pep8.register_check(blankLines)
    pep8.register_check(checkStrings)

    ignore = []
    ignore.append("E501")  # Ignore line length violations.
    ignore.append("E226")  # Ignore too many leading # in comment block.

    critical = []
    critical.append("E301")  # expected 1 blank line, found 0
    critical.append("U302")  # expected 2 blank lines, found 0
    critical.append("E304")  # blank lines found after function decorator
    critical.append("E401")  # multiple imports on one line
    critical.append("E402")  # module level import not at top of file
    critical.append("E713")  # test for membership should be ‘not in’
    critical.append("W191")  # indentation contains tabs
    critical.append("U9")    # Parsing errors (error in this script, or error in code that we're trying to parse)
    critical.append("U")     # All Ultimaker specific stuff.

last_token_multiline = (start[0] != end[0])
        if last_token_multiline:
            rel_indent[end[0] - first_row] = rel_indent[row]

        last_line = line

    if (
        indent_next and
        not last_line_begins_with_multiline and
        pep8.expand_indent(line) == indent_level + DEFAULT_INDENT_SIZE
    ):
        pos = (start[0], indent[0] + 4)
        yield (pos, 'E125 {0}'.format(indent_level +
                                      2 * DEFAULT_INDENT_SIZE))
del pep8._checks['logical_line'][pep8.continued_indentation]
pep8.register_check(continued_indentation)


class FixPEP8(object):

    """Fix invalid code.

    Fixer methods are prefixed "fix_". The _fix_source() method looks for these
    automatically.

    The fixer method can take either one or two arguments (in addition to
    self). The first argument is "result", which is the error information from
    pep8. The second argument, "logical", is required only for logical-line
    fixes.

    The fixer method can return the list of modified lines or None. An empty
    list would mean that no changes were made. None would mean that only the

def main(paths=["."]):
    pep8.register_check(checkNames)
    pep8.register_check(blankLines)
    pep8.register_check(checkStrings)

    ignore = []
    ignore.append("E501")  # Ignore line length violations.
    ignore.append("E226")  # Ignore too many leading # in comment block.

    critical = []
    critical.append("E301")  # expected 1 blank line, found 0
    critical.append("U302")  # expected 2 blank lines, found 0
    critical.append("E304")  # blank lines found after function decorator
    critical.append("E401")  # multiple imports on one line
    critical.append("E402")  # module level import not at top of file
    critical.append("E713")  # test for membership should be ‘not in’
    critical.append("W191")  # indentation contains tabs
    critical.append("U9")    # Parsing errors (error in this script, or error in code that we're trying to parse)

def main(paths=["."]):
    pep8.register_check(checkNames)
    pep8.register_check(blankLines)
    pep8.register_check(checkStrings)

    ignore = []
    ignore.append("E501")  # Ignore line length violations.
    ignore.append("E226")  # Ignore too many leading # in comment block.

    critical = []
    critical.append("E301")  # expected 1 blank line, found 0
    critical.append("U302")  # expected 2 blank lines, found 0
    critical.append("E304")  # blank lines found after function decorator
    critical.append("E401")  # multiple imports on one line
    critical.append("E402")  # module level import not at top of file
    critical.append("E713")  # test for membership should be ‘not in’
    critical.append("W191")  # indentation contains tabs
    critical.append("U9")    # Parsing errors (error in this script, or error in code that we're trying to parse)
    critical.append("U")     # All Ultimaker specific stuff.

# Copyright (c) 2011 - 2016 Detlev Offenbach 
#

"""
Module implementing the code style checker.
"""

import sys
import multiprocessing

import pep8
from NamingStyleChecker import NamingStyleChecker

# register the name checker
pep8.register_check(NamingStyleChecker, NamingStyleChecker.Codes)

from DocStyleChecker import DocStyleChecker
from MiscellaneousChecker import MiscellaneousChecker
from McCabeChecker import McCabeChecker


def initService():
    """
    Initialize the service and return the entry point.
    
    @return the entry point for the background client (function)
    """
    return codeStyleCheck


def initBatchService():