<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_all_publications(return_namedtuples=True):
 """ Get list publications from all available source. Args: return_namedtuples (bool, default True):
 Convert :class:`.Publication` structures to namedtuples (used in AMQP communication). Returns: list: List of :class:`.Publication` structures converted to namedtuple. """

    sources = [
        ben_cz.get_publications,
        grada_cz.get_publications,
        cpress_cz.get_publications,
        zonerpress_cz.get_publications,
    ]

    # get data from all scrappers
    publications = []
    for source in sources:
        publications.extend(
            filters.filter_publications(source())
        )

    # convert to namedtuples
    if return_namedtuples:
        publications = map(lambda x: x.to_namedtuple(), publications)

    return publications