Contract takes a map[string]string and contracts pairs of key and values.

DefaultIf falls back to a default value if the passed value is equal to the condition parameter.

DefaultIfEmpty falls back to a default value if the passed value is empty.

ErrorMessages accumulates the error messages from slice of errors.

Keys extracts the key of a map[string]string and returns them as a slice of strings.

Quote takes a slice of strings and returns a slice of strings where each element of the input is put in double quotation marks.

Transform takes a slice of strings, transforms each element and returns a slice of strings containing the transformed values.