def remove_common_elements(package_list, remove_set):
    """
    Remove the common elements between package_list and remove_set.

    Note that this is *not* an XOR operation: packages that do not
    exist in remove_set (but exists in remove_set) are not included.

    Parameters
    ----------
    package_list : list
        List with string elements representing the packages from the
        requirements file. Assumes that the list has "==" to denote
        package versions.

    remove_set : set
        Set with the names of packages to be removed from requirements.

    Returns
    -------
    list
        List of packages not presented in remove_set.
    """
    package_not_in_remove_set = []
    for package in package_list:
        package_name = package.split("==")[0].strip()
        if package_name not in remove_set:
            package_not_in_remove_set.append(package)
    return package_not_in_remove_set