**Describe the bug** Exporting to csv when a column header starts with '#' results in undefined behavior. **To Reproduce** Steps to reproduce the behavior: 1. run `to_csv` when a column header has '#' in it **Expected behavior** Expected behavior is to get that exact column header in the csv, but instead the column header is treated as a URL fragment. **Screenshots** N/A **Desktop (please complete the following information):** Any **Smartphone (please complete the following information):** Any **Additional context** N/A