Make ASCII Table (Python)

# Adapted From http://stackoverflow.com/questions/5909873/how-can-i-pretty-print-ascii-tables-with-python
def make_table(columns, data):
    """Create an ASCII table and return it as a string.

    Pass a list of strings to use as columns in the table and a list of
    dicts. The strings in 'columns' will be used as the keys to the dicts in
    'data.'

    """
    # Calculate how wide each cell needs to be
    cell_widths = {}
    for c in columns:
        lens = []
        values = [lens.append(len(str(d.get(c, "")))) for d in data]
        lens.append(len(c))
        lens.sort()
        cell_widths[c] = max(lens)

    # Used for formatting rows of data
    row_template = "|" + " {} |" * len(columns)

    # CONSTRUCT THE TABLE

    # The top row with the column titles
    justified_column_heads = [c.ljust(cell_widths[c]) for c in columns]
    header = row_template.format(*justified_column_heads)
    # The second row contains separators
    sep = "|" + "-" * (len(header) - 2) + "|"
    end = "-" * len(header)
    # Rows of data
    rows = []

    for d in data:
        fields = [str(d.get(c, "")).ljust(cell_widths[c]) for c in columns]
        row = row_template.format(*fields)
        rows.append(row)
    rows.append(end)
    return "\n".join([header, sep] + rows)