def template_header(in_template):
    """Extract header from the notebook template.
    
    Args:
        in_template (str): Input notebook template file path.
    
    Returns:
        list: List of lines.
    """    
    header = []
    template_lines = []
    header_end_index = 0

    with open(in_template) as f:
        template_lines = f.readlines()
        for index, line in enumerate(template_lines):
           if '## Add Earth Engine Python script' in line:
                header_end_index = index + 5

    header = template_lines[:header_end_index]

    return header