[FieldTrip] problem reading the .bdf

[Mahmoud]

I have a .bdf file that I want to read in matlab usig ft_read_header()
and ft_read_data().
I have defined a list of channels as
channels = ["CH1" ,   "CH2", "CH3",    "CH4",    "CH5"]

When I try to read the header I get the following error:

hdr = ft_read_header(filename, chanindx= channels);

Error using ft_getopt
the first input should contain key-value pairs

Error in ft_read_header (line 183)
headerformat   = ft_getopt(varargin, 'headerformat');

Can you please let me know what am I doing wrong? I read the help for
ft_read_header() but couldn't figure it out.

Thank you!
Mahmoud