'Gives the header corresponding to this instance as a string.'

def dump(self):

    header = [(self.title.ljust(72) + self.key.ljust(8))]
    header.append(('%14d%14d%14d%14d' % (self.total_nlines, self.pointer_nlines, self.indices_nlines, self.values_nlines)))
    header.append(('%14s%14d%14d%14d%14d' % (self.mxtype.fortran_format.ljust(14), self.nrows, self.ncols, self.nnon_zeros, 0)))
    pffmt = self.pointer_format.fortran_format
    iffmt = self.indices_format.fortran_format
    vffmt = self.values_format.fortran_format
    header.append(('%16s%16s%20s' % (pffmt.ljust(16), iffmt.ljust(16), vffmt.ljust(20))))
    return '\n'.join(header)
