def parse_requirements(strs):
    """Yield ``Requirement`` objects for each specification in `strs`

    `strs` must be a string, or a (possibly-nested) iterable thereof.
    """
    # create a steppable iterator, so we can handle \-continuations
    lines = iter(yield_lines(strs))

    def scan_list(ITEM, TERMINATOR, line, p, groups, item_name):

        items = []

        while not TERMINATOR(line, p):
            if CONTINUE(line, p):
                try:
                    line = next(lines)
                    p = 0
                except __HOLE__:
                    msg = "\\ must not appear on the last nonblank line"
                    raise RequirementParseError(msg)

            match = ITEM(line, p)
            if not match:
                msg = "Expected " + item_name + " in"
                raise RequirementParseError(msg, line, "at", line[p:])

            items.append(match.group(*groups))
            p = match.end()

            match = COMMA(line, p)
            if match:
                # skip the comma
                p = match.end()
            elif not TERMINATOR(line, p):
                msg = "Expected ',' or end-of-list in"
                raise RequirementParseError(msg, line, "at", line[p:])

        match = TERMINATOR(line, p)
        # skip the terminator, if any
        if match:
            p = match.end()
        return line, p, items

    for line in lines:
        match = DISTRO(line)
        if not match:
            raise RequirementParseError("Missing distribution spec", line)
        project_name = match.group(1)
        p = match.end()
        extras = []

        match = OBRACKET(line, p)
        if match:
            p = match.end()
            line, p, extras = scan_list(
                DISTRO, CBRACKET, line, p, (1,), "'extra' name"
            )

        line, p, specs = scan_list(VERSION, LINE_END, line, p, (1, 2),
            "version spec")
        specs = [(op, val) for op, val in specs]
        yield Requirement(project_name, specs, extras)
dataset/ETHPy150Open anzev/hedwig/build/pip/pip/_vendor/pkg_resources/__init__.py/parse_requirements