'Checks for \'intervalness\'
This format is mostly used by galaxy itself.  Valid interval files should include
a valid header comment, but this seems to be loosely regulated.
>>> from galaxy.datatypes.sniff import get_test_fname
>>> fname = get_test_fname( \'test_space.txt\' )
>>> Interval().sniff( fname )
False
>>> fname = get_test_fname( \'interval.interval\' )
>>> Interval().sniff( fname )
True'

def sniff(self, filename):

    try:
        "\n                                                If    we    got    here,    we    already    know    the    file    is_column_based    and    is    not    bed,\n                                                so    we'll    just    look    for    some    valid    data.\n                                                "
        headers = iter_headers(filename, ' DCTB ', comment_designator='#')
        for hdr in headers:
            if hdr:
                if (len(hdr) < 3):
                    return False
                try:
                    int(hdr[1])
                    int(hdr[2])
                except:
                    return False
        return True
    except:
        return False
