-----
    Brief
    -----
    Auxiliary function responsible for checking if the input is a string that contains an url.

    -----------
    Description
    -----------
    Some biosignalsnotebooks functions support a remote access to files. In this situation it is
    important to understand if the input is an url, which can be easily achieved by checking if some
    key-markers are present.

    The key-markers that will be searched are "http://", "https://", "www.", ".pt", ".com", ".org",
    ".net".

    ----------
    Parameters
    ----------
    input_element : unknown
        The data structure that will be checked.

    Returns
    -------
    out : bool
        If the input_element is a string and if it contains any key-marker, then True flag will be returned.

def _is_a_url(input_element):
    """
    -----
    Brief
    -----
    Auxiliary function responsible for checking if the input is a string that contains an url.

    -----------
    Description
    -----------
    Some biosignalsnotebooks functions support a remote access to files. In this situation it is
    important to understand if the input is an url, which can be easily achieved by checking if some
    key-markers are present.

    The key-markers that will be searched are "http://", "https://", "www.", ".pt", ".com", ".org",
    ".net".

    ----------
    Parameters
    ----------
    input_element : unknown
        The data structure that will be checked.

    Returns
    -------
    out : bool
        If the input_element is a string and if it contains any key-marker, then True flag will be returned.
    """
    if type(input_element) is str:
        # Check if signal_handler is a url.
        # [Statements to be executed if signal_handler is a url]
        if any(mark in input_element for mark in ["http://", "https://", "www.", ".pt", ".com",
                                                  ".org", ".net"]):
            return True
        else:
            return False
    else:
        return False