import re


def from_camelcase(inStr):
    """Converts a string from camelCase to snake_case

    >>> from_camelcase('convertToPythonicCase')
    'convert_to_pythonic_case'

    Args:
        inStr (str): String to convert

    Returns:
        String formatted as snake_case
    """
    return re.sub('[A-Z]', lambda x: '_' + x.group(0).lower(), inStr)