<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _remove_empty_lines(self, lines):
 """ Iterate through the lines and remove any that are either empty or contain only one whitespace value Parameters lines : array-like The array of lines that we are to filter. Returns ------- filtered_lines : array-like The same array of lines with the "empty" ones removed. """


        ret = []
        for l in lines:
            # Remove empty lines and lines with only one whitespace value
            if (len(l) > 1 or len(l) == 1 and
                    (not isinstance(l[0], str) or l[0].strip())):
                ret.append(l)
        return ret