human
Complete this python program:
def get_yaml_from_header(header):
assistant
#Here is the Python code you requested.

    """Return lines with a YAML representation of header content from a Table.
    The ``header`` dict must contain these keys:
    - \cols\ : list of table column objects (required)
    - \meta\ : table \meta\ attribute (optional)
    Other keys included in ``header`` will be serialized in the output YAML
    representation.
    Parameters
    header : dict
    Table header content
    Returns
    lines : list
    List of text lines with YAML header content
    """
    try:
        import yaml
    except ImportError:
        raise ImportError('`import    yaml`    failed,    PyYAML    package    is    required    for    ECSV    format')
    from ..io.misc.yaml import AstropyDumper
    class TableDumper(AstropyDumper, ):
        '\n                                Custom    Dumper    that    represents    OrderedDict    as    an    !!omap    object.\n                                '
        def represent_mapping(self, tag, mapping, flow_style=None):
            '\n                                                This    is    a    combination    of    the    Python    2    and    3    versions    of    this    method\n                                                in    the    PyYAML    library    to    allow    the    required    key    ordering    via    the\n                                                ColumnOrderList    object.        The    Python    3    version    insists    on    turning    the\n                                                items()    mapping    into    a    list    object    and    sorting,    which    results    in\n                                                alphabetical    order    for    the    column    keys.\n                                                '
            value = []
            node = yaml.MappingNode(tag, value, flow_style=flow_style)
            if (self.alias_key is not None):
                self.represented_objects[self.alias_key] = node
            best_style = True
            if hasattr(mapping, 'items'):
                mapping = mapping.items()
                if hasattr(mapping, 'sort'):
                    mapping.sort()
                else:
                    mapping = list(mapping)
                    try:
                        mapping = sorted(mapping)
                    except TypeError:
                        pass
            for (item_key, item_value) in mapping:
                node_key = self.represent_data(item_key)
                node_value = self.represent_data(item_value)
              ...