def is_alpha(character):
    """
    Checks if the given character represents an alphabet
    letter. This is a complex operation as many comparison
    operations must be performed.

    :rtype: bool
    :return: If the given character represents an alphabet
    letter.
    """
    return (character >= 'a' and character <= 'z' or character >= '0' and 
        character <= '9' or character >= 'A' and character <= 'Z' or 
        character == '_' or character == '$' or character == '\\' or 
        character is not None and ord(character) > 126)
