from typing import TextIO


def skip_header(reader: TextIO) -> str:
        """Skip the header in reader and return the first real piece of data.
        >>> infile = StringIO('Example\\n# Comment\\n# Comment\\nData line\\n')
        >>> skip_header(infile)
        'Data line\\n'
        """
        # Read the description line
        line = reader.readline()
        # Find the first non-comment line
        line = reader.readline()
        while line.startswith('#'):
                line = reader.readline()
        # Now line contains the first real piece of data
        return line